RichTextBox periodically crashing application

[Michael]

We utilize the telerik RichTextBox control within a large WPF application for editing HTML email templates we pull down from a web service.  

One of the people in the office is receiving an error occasionally which is causing the application to crash when they load one of the UIs where the Telerik RichTextBox exists.  

This is the exception message that is being logged:

2013-10-08 08:56:25,252 [1] ERROR App - Application_DispatcherUnhandledException
System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.Windows.Documents.UI.DocumentWebLayoutPresenter.FocusCaret(Boolean forceFocus)
   at Telerik.Windows.Documents.UI.DocumentWebLayoutPresenter.<SetupUILayers>b__1()
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
2013-10-08 08:56:25,445 [1] ERROR App - Unhandled Exception
System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.Windows.Documents.UI.DocumentWebLayoutPresenter.FocusCaret(Boolean forceFocus)
   at Telerik.Windows.Documents.UI.DocumentWebLayoutPresenter.<SetupUILayers>b__1()
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
2013-10-08 08:56:25,640 [1] ERROR App - Exception in App.HandleException calling ExceptionPolicy.HandleExecption: Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionHandlingException: The current build operation (build key Build Key[Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl, Default Policy]) failed: Object reference not set to an instance of an object. (Strategy type ConfiguredObjectStrategy, index 2) ---> Microsoft.Practices.ObjectBuilder2.BuildFailedException: The current build operation (build key Build Key[Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl, Default Policy]) failed: Object reference not set to an instance of an object. (Strategy type ConfiguredObjectStrategy, index 2) ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionHandlingConfigurationView.GetExceptionPolicyData(String policyName)
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyCustomFactory.GetConfiguration(String id, IConfigurationSource configurationSource)
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyCustomFactory.CreateObject(IBuilderContext context, String name, IConfigurationSource configurationSource, ConfigurationReflectionCache reflectionCache)
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder.ConfiguredObjectStrategy.PreBuildUp(IBuilderContext context)
   at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context)
   --- End of inner exception stack trace ---
   at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context)
   at Microsoft.Practices.ObjectBuilder2.Builder.BuildUp(IReadWriteLocator locator, ILifetimeContainer lifetime, IPolicyList policies, IStrategyChain strategies, Object buildKey, Object existing)
   at Microsoft.Practices.ObjectBuilder2.Builder.BuildUp[TTypeToBuild](IReadWriteLocator locator, ILifetimeContainer lifetime, IPolicyList policies, IStrategyChain strategies, Object buildKey, Object existing)
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder.EnterpriseLibraryFactory.BuildUp[T](IReadWriteLocator locator, ILifetimeContainer lifetimeContainer, String id, IConfigurationSource configurationSource)
   at Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder.LocatorNameTypeFactoryBase`1.Create(String name)
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.GetExceptionPolicy(Exception exception, String policyName, ExceptionPolicyFactory factory)
   --- End of inner exception stack trace ---
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.GetExceptionPolicy(Exception exception, String policyName, ExceptionPolicyFactory factory)
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.HandleException(Exception exceptionToHandle, String policyName, ExceptionPolicyFactory policyFactory)
   at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.HandleException(Exception exceptionToHandle, String policyName)
   at App.HandleException(Exception ex)

This is the XAML for the control:

xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"

<telerik:HtmlDataProvider x:Name="_htmlDataProvider"
                          Html="{Binding Path=DocumentInvitationEmailTemplate, Mode=TwoWay}"
                          RichTextBox="{Binding ElementName=_richTextBox}" />

<telerik:RadRichTextBox x:Name="_richTextBox"
                        Margin="4"
                        BorderBrush="Gray"
                        AcceptsReturn="True"
                        AcceptsTab="True"
                        AllowDrop="True"
                        AllowScaling="True"
                        ScrollViewer.VerticalScrollBarVisibility="Auto"
                        Grid.Row="1" />

<telerik:RadRichTextBoxRibbonUI x:Name="_richTextBoxRibbon" CollapseThresholdSize="50,50"
                                DataContext="{Binding Commands, ElementName=_richTextBox}"
                                VerticalAlignment="Top">
    <telerik:RadRichTextBoxRibbonUI.Resources>
        <telerik:FontFamiliesProvider x:Key="FontFamiliesProvider" />
        <telerik:EditingContextTypeToBoolConverter x:Key="EditingContextTypeToBoolConverter" />
    </telerik:RadRichTextBoxRibbonUI.Resources>
    <telerik:RadRichTextBoxRibbonUI.Backstage>
        <telerik:RadRibbonBackstage>
            <telerik:RadRibbonBackstageItem Header="Open"
                                            Icon="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/open.png"
                                            IsSelectable="false"
                                            telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding OpenDocumentCommand}" />
            <telerik:RadRibbonBackstageItem Header="Save"
                                            Icon="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/save.png"
                                            IsSelectable="false"
                                            telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding SaveCommand}" />
            <telerik:RadRibbonBackstageItem Header="Save As"
                                            Icon="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/saveas.png"
                                            IsDefault="false">
                <StackPanel HorizontalAlignment="Stretch"
                            Margin="20,20,0,0"
                            UseLayoutRounding="True">
                    <TextBlock Foreground="#FF5E5E7C"
                               FontWeight="ExtraBold"
                               FontSize="18"
                               FontFamily="Verdana"
                               Text="Save As" />
                    <Rectangle Fill="Gray"
                               HorizontalAlignment="Left"
                               Height="1"
                               Width="410" />
                    <StackPanel Margin="0,30,0,0"
                                Orientation="Horizontal">
                        <telerik:RadRibbonButton BorderBrush="Gray"
                                                 CommandParameter="html"
                                                 CornerRadius="3"
                                                 Height="80"
                                                 telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding SaveCommand}"
                                                 telerik:RadRichTextBoxRibbonUI.ShouldCloseBackstage="True"
                                                 VerticalContentAlignment="Center"
                                                 Width="90">
                            <Image HorizontalAlignment="Center"
                                   Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/ApplicationMenu/html.png"
                                   Stretch="None" />
                        </telerik:RadRibbonButton>
                        <StackPanel Margin="20 0 0 0">
                            <TextBlock Foreground="#FF5E5E7C"
                                       FontWeight="ExtraBold"
                                       FontSize="18"
                                       Text="HTML Document" />
                            <TextBlock FontSize="13"
                                       FontFamily="Verdana"
                                       TextWrapping="Wrap"
                                       Text="Save the file as a HTML document."
                                       Width="300" />
                        </StackPanel>
                    </StackPanel>
                    <StackPanel Margin="0,30,0,0"
                                Orientation="Horizontal">
                        <telerik:RadRibbonButton BorderBrush="Gray"
                                                 CommandParameter="txt"
                                                 CornerRadius="3"
                                                 Height="80"
                                                 telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding SaveCommand}"
                                                 telerik:RadRichTextBoxRibbonUI.ShouldCloseBackstage="True"
                                                 VerticalContentAlignment="Center"
                                                 Width="90">
                            <Image HorizontalAlignment="Center"
                                   Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/ApplicationMenu/PlainText.png"
                                   Stretch="None" />
                        </telerik:RadRibbonButton>
                        <StackPanel Margin="20 0 0 0">
                            <TextBlock Foreground="#FF5E5E7C"
                                       FontWeight="ExtraBold"
                                       FontSize="18"
                                       Text="Plain text" />
                            <TextBlock FontSize="13"
                                       FontFamily="Verdana"
                                       TextWrapping="Wrap"
                                       Text="Save document in plain text format."
                                       Width="300" />
                        </StackPanel>
                    </StackPanel>
                </StackPanel>
            </telerik:RadRibbonBackstageItem>
            <telerik:RadRibbonBackstageItem Header="Print"
                                            Icon="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/print.png"
                                            IsDefault="true">
                <StackPanel HorizontalAlignment="Stretch"
                            Margin="20,20,0,0"
                            UseLayoutRounding="True">
                    <TextBlock Foreground="#FF5E5E7C"
                               FontWeight="ExtraBold"
                               FontSize="18"
                               FontFamily="Verdana"
                               Text="Print" />
                    <Rectangle Fill="Gray"
                               HorizontalAlignment="Left"
                               Height="1"
                               Width="410" />
                    <StackPanel Margin="0,30,0,0"
                                Orientation="Horizontal">
                        <telerik:RadRibbonButton BorderBrush="Gray"
                                                 CommandParameter="Native"
                                                 CornerRadius="3"
                                                 Height="80"
                                                 telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding PrintCommand}"
                                                 telerik:RadRichTextBoxRibbonUI.ShouldCloseBackstage="True"
                                                 VerticalContentAlignment="Center"
                                                 Width="90">
                            <Image HorizontalAlignment="Center"
                                   Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/ApplicationMenu/pagesetup.png"
                                   Stretch="None" />
                        </telerik:RadRibbonButton>
                        <StackPanel Margin="20 0 0 0">
                            <TextBlock Foreground="#FF5E5E7C"
                                       FontWeight="ExtraBold"
                                       FontSize="18"
                                       Text="Native Print" />
                            <TextBlock FontSize="13"
                                       FontFamily="Verdana"
                                       TextWrapping="Wrap"
                                       Text="Send the document directly to the default printer without making changes."
                                       Width="300" />
                        </StackPanel>
                    </StackPanel>
                </StackPanel>
            </telerik:RadRibbonBackstageItem>
        </telerik:RadRibbonBackstage>
    </telerik:RadRichTextBoxRibbonUI.Backstage>
    <telerik:RadRichTextBoxRibbonUI.ContextualGroups>
        <telerik:RadRibbonContextualGroup x:Name="TableTools"
                                          Header="Table Tools">
            <telerik:RadRibbonContextualGroup.IsActive>
                <Binding Converter="{StaticResource EditingContextTypeToBoolConverter}"
                         Mode="OneWay"
                         Path="AssociatedRichTextBox.CurrentEditingContext.Type">
                    <Binding.ConverterParameter>
                        <telerik:EditingContextTypes>Table</telerik:EditingContextTypes>
                    </Binding.ConverterParameter>
                </Binding>
            </telerik:RadRibbonContextualGroup.IsActive>
        </telerik:RadRibbonContextualGroup>
        <telerik:RadRibbonContextualGroup x:Name="HeaderFooterTools"
                                          Header="Header & Footer Tools">
            <telerik:RadRibbonContextualGroup.IsActive>
                <Binding Converter="{StaticResource EditingContextTypeToBoolConverter}"
                         Mode="OneWay"
                         Path="AssociatedRichTextBox.CurrentEditingContext.Type">
                    <Binding.ConverterParameter>
                        <telerik:EditingContextTypes>HeaderFooter</telerik:EditingContextTypes>
                    </Binding.ConverterParameter>
                </Binding>
            </telerik:RadRibbonContextualGroup.IsActive>
        </telerik:RadRibbonContextualGroup>
    </telerik:RadRichTextBoxRibbonUI.ContextualGroups>
    <telerik:RadRichTextBoxRibbonUI.QuickAccessToolBar>
        <telerik:QuickAccessToolBar>
            <telerik:RadRibbonButton telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding SaveCommand}"
                                     Size="Small"
                                     SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/save.png"
                                     Text="Save" />
            <telerik:RadRibbonSplitButton telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding UndoCommand}"
                                          Size="Small"
                                          SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/undo.png"
                                          Text="Undo">
                <telerik:RadRibbonSplitButton.DropDownContent>
                    <telerik:MultipleUndoControl telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding MultipleUndoCommand}" />
                </telerik:RadRibbonSplitButton.DropDownContent>
            </telerik:RadRibbonSplitButton>
            <telerik:RadRibbonButton telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding RedoCommand}"
                                     Size="Small"
                                     SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/redo.png"
                                     Text="Redo" />
        </telerik:QuickAccessToolBar>
    </telerik:RadRichTextBoxRibbonUI.QuickAccessToolBar>
    <telerik:RadRibbonTab Header="Home">
        <telerik:RadRibbonGroup Header="Clipboard">
            <telerik:RadCollapsiblePanel>
                <telerik:RadRibbonButton CollapseToSmall="WhenGroupIsMedium"
                                         telerik:ScreenTip.Description="Cut the selection and put it on the Clipboard."
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding CutCommand}"
                                         Size="Medium"
                                         SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/cut.png"
                                         Text="Cut"
                                         telerik:ScreenTip.Title="Cut" />
                <telerik:RadRibbonButton CollapseToSmall="WhenGroupIsMedium"
                                         telerik:ScreenTip.Description="Copy the selection and put it on the Clipboard."
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding CopyCommand}"
                                         Size="Medium"
                                         SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/copy.png"
                                         Text="Copy"
                                         telerik:ScreenTip.Title="Copy" />
                <telerik:RadRibbonButton CollapseToSmall="WhenGroupIsMedium"
                                         telerik:ScreenTip.Description="Paste the contents of the Clipboard."
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding PasteCommand}"
                                         Size="Medium"
                                         SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/paste.png"
                                         Text="Paste"
                                         telerik:ScreenTip.Title="Paste" />
            </telerik:RadCollapsiblePanel>
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup DialogLauncherVisibility="Visible"
                                telerik:ScreenTip.Description="Show the font dialog box."
                                Header="Font"
                                telerik:ScreenTip.Icon="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/FontDialog.png"
                                telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowFontPropertiesDialogCommand}"
                                telerik:ScreenTip.Title="Font">
            <telerik:RadOrderedWrapPanel>
                <StackPanel Orientation="Horizontal">
                    <telerik:RadRibbonComboBox CanAutocompleteSelectItems="False"
                                               CanKeyboardNavigationSelectItems="False"
                                               CommandParameter="{Binding SelectedValue, RelativeSource={RelativeSource Self}}"
                                               telerik:ScreenTip.Description="Change the font family."
                                               IsReadOnly="True"
                                               ItemsSource="{Binding RegisteredFonts, Source={StaticResource FontFamiliesProvider}}"
                                               MaxDropDownHeight="400"
                                               OpenDropDownOnFocus="True"
                                               telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeFontFamilyCommand}"
                                               telerik:ScreenTip.Title="Font"
                                               Width="132" />
                    <telerik:RadRibbonComboBox CanAutocompleteSelectItems="False"
                                               CanKeyboardNavigationSelectItems="False"
                                               CommandParameter="{Binding SelectedItem.Tag, RelativeSource={RelativeSource Self}}"
                                               telerik:ScreenTip.Description="Change the font size."
                                               IsEditable="True"
                                               IsReadOnly="True"
                                               IsTextSearchEnabled="False"
                                               MaxDropDownHeight="400"
                                               OpenDropDownOnFocus="True"
                                               telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeFontSizeCommand}"
                                               telerik:ScreenTip.Title="Font Size"
                                               Width="65">
                        <telerik:RadRibbonComboBoxItem Content="8"
                                                       Tag="10.67" />
                        <telerik:RadRibbonComboBoxItem Content="9"
                                                       Tag="12" />
                        <telerik:RadRibbonComboBoxItem Content="10"
                                                       Tag="13.34" />
                        <telerik:RadRibbonComboBoxItem Content="11"
                                                       Tag="14.67" />
                        <telerik:RadRibbonComboBoxItem Content="12"
                                                       Tag="16" />
                        <telerik:RadRibbonComboBoxItem Content="14"
                                                       Tag="18.67" />
                        <telerik:RadRibbonComboBoxItem Content="16"
                                                       Tag="21.33" />
                        <telerik:RadRibbonComboBoxItem Content="18"
                                                       Tag="24" />
                        <telerik:RadRibbonComboBoxItem Content="20"
                                                       Tag="26.67" />
                        <telerik:RadRibbonComboBoxItem Content="22"
                                                       Tag="29.33" />
                        <telerik:RadRibbonComboBoxItem Content="24"
                                                       Tag="32" />
                        <telerik:RadRibbonComboBoxItem Content="26"
                                                       Tag="34.67" />
                        <telerik:RadRibbonComboBoxItem Content="28"
                                                       Tag="37.33" />
                        <telerik:RadRibbonComboBoxItem Content="36"
                                                       Tag="48" />
                        <telerik:RadRibbonComboBoxItem Content="48"
                                                       Tag="64" />
                        <telerik:RadRibbonComboBoxItem Content="72"
                                                       Tag="96" />
                    </telerik:RadRibbonComboBox>
                </StackPanel>
                <telerik:RadButtonGroup>
                    <telerik:RadRibbonButton telerik:ScreenTip.Description="Increase the font size."
                                             telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding IncrementFontSizeCommand}"
                                             Size="Small"
                                             SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/font-increasesize.png"
                                             telerik:ScreenTip.Title="Grow Font" />
                    <telerik:RadRibbonButton telerik:ScreenTip.Description="Decrease the font size."
                                             telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding DecrementFontSizeCommand}"
                                             Size="Small"
                                             SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/font-decreasesize.png"
                                             telerik:ScreenTip.Title="Shrink Font" />
                </telerik:RadButtonGroup>
                <telerik:RadButtonGroup>
                    <telerik:RadRibbonButton telerik:ScreenTip.Description="Clear all the formatting from the selection, leaving only the plain text."
                                             telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ClearAllFormattingCommand}"
                                             Size="Small"
                                             SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/ClearFormatting16.png"
                                             telerik:ScreenTip.Title="Clear All Formatting" />
                </telerik:RadButtonGroup>
                <telerik:RadButtonGroup>
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Make the selected text bold."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleBoldCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/bold.png"
                                                   telerik:ScreenTip.Title="Bold" />
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Italicize the selected text."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleItalicCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/italic.png"
                                                   telerik:ScreenTip.Title="Italic" />
                    <telerik:RadRibbonSplitButton telerik:ScreenTip.Description="Underline the selected text."
                                                  IsToggle="True"
                                                  telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleUnderlineCommand}"
                                                  SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/underline.png"
                                                  telerik:ScreenTip.Title="Underline">
                        <telerik:RadRibbonSplitButton.DropDownContent>
                            <telerik:RadGallery Height="210"
                                                ItemWidth="156"
                                                ItemHeight="26"
                                                telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeUnderlineDecorationCommand}"
                                                ViewportWidth="157">
                                <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/underline1.png"
                                                        Tag="Line" />
                                <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/underline2.png"
                                                        Tag="DoubleLine" />
                                <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/underline3.png"
                                                        Tag="ThickLine" />
                                <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/underline4.png"
                                                        Tag="DottedLine" />
                                <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/underline5.png"
                                                        Tag="DashedLine" />
                                <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/underline6.png"
                                                        Tag="DotDashedLine" />
                                <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/underline7.png"
                                                        Tag="DotDotDashedLine" />
                                <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/underline8.png"
                                                        Tag="Wave" />
                            </telerik:RadGallery>
                        </telerik:RadRibbonSplitButton.DropDownContent>
                    </telerik:RadRibbonSplitButton>
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Draw a line through the middle of the selected text."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleStrikethroughCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/Strikethrough16.png"
                                                   telerik:ScreenTip.Title="Strikethrough" />
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Create small letters below the text baseline."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleSubscriptCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/subscript.png"
                                                   telerik:ScreenTip.Title="Subscript" />
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Create small text above the line of text."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleSuperscriptCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/superscript.png"
                                                   telerik:ScreenTip.Title="Superscript" />
                </telerik:RadButtonGroup>
                <telerik:RadButtonGroup>
                    <telerik:HighlightColorPicker AutomaticColor="Transparent"
                                                  BorderThickness="0"
                                                  telerik:ScreenTip.Description="Make text look like it was marked with a highlighter pen."
                                                  Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/highlight.png"
                                                  NoColorText="No color"
                                                  telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeFontHighlightColorCommand}"
                                                  SelectedColor="Yellow"
                                                  telerik:ScreenTip.Title="Text Highlight Color" />
                    <telerik:HighlightColorPicker BorderThickness="0"
                                                  telerik:ScreenTip.Description="Change the text color."
                                                  Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/FontForeColor.png"
                                                  telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeFontForeColorCommand}"
                                                  SelectedColor="Red"
                                                  telerik:ScreenTip.Title="Font Color" />
                </telerik:RadButtonGroup>
            </telerik:RadOrderedWrapPanel>
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup DialogLauncherVisibility="Visible"
                                telerik:ScreenTip.Description="Show the Paragraph dialog box."
                                Header="Paragraph"
                                telerik:ScreenTip.Icon="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/PropertiesDialog.png"
                                telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowParagraphPropertiesDialogCommand}"
                                telerik:ScreenTip.Title="Paragraph">
            <telerik:RadOrderedWrapPanel>
                <telerik:RadButtonGroup>
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Start a bulleted list."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleBulletsCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/list-bullets.png"
                                                   telerik:ScreenTip.Title="Bullets" />
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Start a numbered list."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleNumberedCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/list-numbered.png"
                                                   telerik:ScreenTip.Title="Numbering" />
                    <telerik:RadRibbonDropDownButton telerik:ScreenTip.Description="Start a multilevel list. Click the arrow to choose different multilevel list styles."
                                                     Size="Small"
                                                     SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/MultilevelList.png"
                                                     telerik:ScreenTip.Title="Multilevel List">
                        <telerik:RadRibbonDropDownButton.DropDownContent>
                            <StackPanel>
                                <ScrollViewer MaxHeight="565">
                                    <StackPanel>
                                        <telerik:RadGroupHeader Content="List Library" />
                                        <telerik:RadGallery Height="176"
                                                            ItemWidth="88"
                                                            ItemHeight="88"
                                                            telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeListStyleCommand}"
                                                            ScrollViewer.VerticalScrollBarVisibility="Disabled"
                                                            ViewportWidth="266">
                                            <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/MultilevelListNone.png"
                                                                    Tag="None" />
                                            <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/MultilevelListBulleted.png"
                                                                    Tag="Bulleted" />
                                            <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/MultilevelListNumbered.png"
                                                                    Tag="Numbered" />
                                            <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/MultilevelListNumberedParenthesis.png"
                                                                    Tag="NumberedParenthesis" />
                                            <telerik:RadGalleryItem Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/MultilevelListNumberedHierarchical.png"
                                                                    Tag="NumberedHierarchical" />
                                        </telerik:RadGallery>
                                        <telerik:ListStylesGallery AssociatedRichTextBox="{Binding AssociatedRichTextBox, Mode=OneWay}" />
                                    </StackPanel>
                                </ScrollViewer>
                                <telerik:RadRibbonButton HorizontalAlignment="Stretch"
                                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowDefineNewListStyleDialogCommand}"
                                                         Size="Medium"
                                                         Text="Define New List Style ..." />
                            </StackPanel>
                        </telerik:RadRibbonDropDownButton.DropDownContent>
                    </telerik:RadRibbonDropDownButton>
                </telerik:RadButtonGroup>
                <telerik:RadButtonGroup>
                    <telerik:RadRibbonButton telerik:ScreenTip.Description="Decrease the indent level of the paragraph."
                                             telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding DecrementParagraphLeftIndentCommand}"
                                             Size="Small"
                                             SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/outdent.png"
                                             telerik:ScreenTip.Title="Decrease Indent" />
                    <telerik:RadRibbonButton telerik:ScreenTip.Description="Increase the indent level of the paragraph."
                                             telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding IncrementParagraphLeftIndentCommand}"
                                             Size="Small"
                                             SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/indent.png"
                                             telerik:ScreenTip.Title="Increase Indent" />
                </telerik:RadButtonGroup>
                <telerik:RadButtonGroup>
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Set the direction of text to be displayed from left to right."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeParagraphFlowDirectionCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/LeftToRightFlowDirection.png"
                                                   Text="Left-to-Right Text Direction"
                                                   telerik:ScreenTip.Title="Left-To-Right Text Direction">
                        <telerik:RadRibbonToggleButton.CommandParameter>
                            <FlowDirection>LeftToRight</FlowDirection>
                        </telerik:RadRibbonToggleButton.CommandParameter>
                    </telerik:RadRibbonToggleButton>
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Set the direction of text to be displayed from right to left."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeParagraphFlowDirectionCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/RightToLeftFlowDirection.png"
                                                   Text="Right-to-Left Text Direction"
                                                   telerik:ScreenTip.Title="Right-To-Left Text Direction">
                        <telerik:RadRibbonToggleButton.CommandParameter>
                            <FlowDirection>RightToLeft</FlowDirection>
                        </telerik:RadRibbonToggleButton.CommandParameter>
                    </telerik:RadRibbonToggleButton>
                </telerik:RadButtonGroup>
                <telerik:RadButtonGroup>
                    <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Show paragraph marks and other hidden formatting symbols."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleFormattingSymbolsCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/formatting-symbols.png"
                                                   telerik:ScreenTip.Title="Show/Hide Formatting Symbols" />
                </telerik:RadButtonGroup>
                <telerik:RadButtonGroup>
                    <telerik:RadRibbonToggleButton CommandParameter="Left"
                                                   telerik:ScreenTip.Description="Align text to the left."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeTextAlignmentCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/alignleft.png"
                                                   Text="Align Left"
                                                   telerik:ScreenTip.Title="Align Text Left" />
                    <telerik:RadRibbonToggleButton CommandParameter="Center"
                                                   telerik:ScreenTip.Description="Center text."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeTextAlignmentCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/aligncenter.png"
                                                   Text="Center"
                                                   telerik:ScreenTip.Title="Center" />
                    <telerik:RadRibbonToggleButton CommandParameter="Right"
                                                   telerik:ScreenTip.Description="Align text to the right."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeTextAlignmentCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/alignright.png"
                                                   Text="Align Right"
                                                   telerik:ScreenTip.Title="Align Text Right" />
                    <telerik:RadRibbonToggleButton CommandParameter="Justify"
                                                   telerik:ScreenTip.Description="Align text to both left and right margins, adding extra space between words as necessary."
                                                   telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeTextAlignmentCommand}"
                                                   Size="Small"
                                                   SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/alignjustify.png"
                                                   Text="Justify"
                                                   telerik:ScreenTip.Title="Justify" />
                </telerik:RadButtonGroup>
                <telerik:RadButtonGroup>
                    <telerik:HighlightColorPicker AutomaticColor="Transparent"
                                                  BorderThickness="0"
                                                  telerik:ScreenTip.Description="Color the background behind the selected paragraph."
                                                  Image="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/ParagraphBackgroundColor.png"
                                                  NoColorText="No color"
                                                  telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeParagraphBackgroundColorCommand}"
                                                  SelectedColor="Transparent"
                                                  telerik:ScreenTip.Title="Shading" />
                </telerik:RadButtonGroup>
            </telerik:RadOrderedWrapPanel>
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Styles">
            <telerik:StylesGallery AssociatedRichTextBox="{Binding AssociatedRichTextBox, Mode=OneWay}" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Change the set of styles, colors, fonts and paragraph spacing used in this document."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/ChangeStyles.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowManageStylesDialogCommand}"
                                     Size="Large"
                                     Text="Change Styles"
                                     telerik:ScreenTip.Title="Change Styles" />
        </telerik:RadRibbonGroup>
    </telerik:RadRibbonTab>
    <telerik:RadRibbonTab Header="Insert">
        <telerik:RadRibbonGroup Header="Tables">
            <telerik:RadRibbonDropDownButton CollapseToMedium="WhenGroupIsMedium"
                                             Command="{Binding InsertTableCommand}"
                                             telerik:ScreenTip.Description="Insert a table into the document."
                                             LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/InsertTable.png"
                                             Size="Large"
                                             Text="Table"
                                             telerik:ScreenTip.Title="Table">
                <telerik:RadRibbonDropDownButton.DropDownContent>
                    <StackPanel>
                        <telerik:RadRibbonButton ClickMode="Press">
                            <telerik:TableSizePicker Command="{Binding InsertTableCommand}" />
                        </telerik:RadRibbonButton>
                        <telerik:RadMenuItem IsSeparator="True" />
                        <telerik:RadRibbonButton HorizontalAlignment="Stretch"
                                                 telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowInsertTableDialogCommand}"
                                                 Size="Medium"
                                                 SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/InsertTable.png"
                                                 Text="Insert Table..." />
                    </StackPanel>
                </telerik:RadRibbonDropDownButton.DropDownContent>
            </telerik:RadRibbonDropDownButton>
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Links">
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Create a link to a Web page, a picture or an e-mail address."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/inserthyperlink.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowInsertHyperlinkDialogCommand}"
                                     Size="Large"
                                     Text="Hyperlink"
                                     telerik:ScreenTip.Title="Insert Hyperlink" />
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Symbols">
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Insert symbols that are not on your keyboard, such as copyright symbols, trademark symbols, paragraph marks, and Unicode characters."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/Symbol.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowInsertSymbolWindowCommand}"
                                     Size="Large"
                                     Text="Symbol"
                                     telerik:ScreenTip.Title="Insert Symbol" />
        </telerik:RadRibbonGroup>
    </telerik:RadRibbonTab>
    <telerik:RadRibbonTab ContextualGroupName="TableTools"
                          Header="Layout">
        <telerik:RadRibbonGroup Header="Table">
            <telerik:RadRibbonDropDownButton CollapseToMedium="WhenGroupIsMedium"
                                             Command="{Binding SelectTableEmptyCommand}"
                                             telerik:ScreenTip.Description="Select rows, columns, cells, or the entire table."
                                             LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/SelectTableTools.png"
                                             Size="Large"
                                             Text="Select"
                                             telerik:ScreenTip.Title="Select Table">
                <telerik:RadRibbonDropDownButton.DropDownContent>
                    <StackPanel>
                        <telerik:RadRibbonButton telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding SelectTableCellCommand}"
                                                 Size="Medium"
                                                 SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/SelectTableCell.png"
                                                 Text="Select Cell" />
                        <telerik:RadRibbonButton telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding SelectTableColumnCommand}"
                                                 Size="Medium"
                                                 SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/SelectTableColumn.png"
                                                 Text="Select Column" />
                        <telerik:RadRibbonButton telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding SelectTableRowCommand}"
                                                 Size="Medium"
                                                 SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/SelectTableRow.png"
                                                 Text="Select Row" />
                        <telerik:RadRibbonButton telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding SelectTableCommand}"
                                                 Size="Medium"
                                                 SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/SelectTable.png"
                                                 Text="Select Table" />
                    </StackPanel>
                </telerik:RadRibbonDropDownButton.DropDownContent>
            </telerik:RadRibbonDropDownButton>
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Show the Table Properties dialog box to change advanced table properties."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/TableProperties.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowTablePropertiesDialogCommand}"
                                     Size="Large"
                                     Text="Properties"
                                     telerik:ScreenTip.Title="Table Properties" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Delete the entire table."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/DeleteTable.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding DeleteTableCommand}"
                                     Size="Large"
                                     Text="Delete"
                                     telerik:ScreenTip.Title="Delete Table" />
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Rows">
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Insert a new row."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/InsertTableRow.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding InsertTableRowCommand}"
                                     Size="Large"
                                     Text="Insert Row"
                                     telerik:ScreenTip.Title="Insert Row" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Add a new row directly below the selected row."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/InsertTableRowBelow.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding InsertTableRowBelowCommand}"
                                     Size="Large"
                                     Text="Insert Below"
                                     telerik:ScreenTip.Title="Insert Rows Below" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Add a new row directly above the selected row."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/InsertTableRowAbove.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding InsertTableRowAboveCommand}"
                                     Size="Large"
                                     Text="Insert Above"
                                     telerik:ScreenTip.Title="Insert Rows Above" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Delete the selected row."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/DeleteTableRows.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding DeleteTableRowCommand}"
                                     Size="Large"
                                     Text="Delete Row"
                                     telerik:ScreenTip.Title="Delete Row" />
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Columns">
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Insert a new column."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/InsertTableColumn.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding InsertTableColumnCommand}"
                                     Size="Large"
                                     Text="Insert Column"
                                     telerik:ScreenTip.Title="Insert Column" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Add a new column directly to the left of the selected column."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/InsertTableColumnToTheLeft.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding InsertTableColumnToTheLeftCommand}"
                                     Size="Large"
                                     Text="Insert Left"
                                     telerik:ScreenTip.Title="Insert Columns to the Left" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Add a new column directly to the right of the selected column."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/InsertTableColumnToTheRight.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding InsertTableColumnToTheRightCommand}"
                                     Size="Large"
                                     Text="Insert Right"
                                     telerik:ScreenTip.Title="Insert Columns to the Right" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Delete the selected column."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/DeleteTableColumns.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding DeleteTableColumnCommand}"
                                     Size="Large"
                                     Text="Delete Column"
                                     telerik:ScreenTip.Title="Delete Column" />
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Merge">
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Merge the selected cells into one cell."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/MergeTableCells.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding MergeTableCellsCommand}"
                                     Size="Large"
                                     Text="Merge Cells"
                                     telerik:ScreenTip.Title="Merge Cells" />
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Cell Size">
            <telerik:RadRibbonDropDownButton CollapseToMedium="WhenGroupIsMedium"
                                             Command="{Binding SelectTableEmptyCommand}"
                                             telerik:ScreenTip.Description="Automatically resize the column widths based on the size of the text in them or keep the widths with fixed size."
                                             LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/AutoFit.png"
                                             Size="Large"
                                             Text="AutoFit"
                                             telerik:ScreenTip.Title="AutoFit/Fixed">
                <telerik:RadRibbonDropDownButton.DropDownContent>
                    <StackPanel>
                        <telerik:RadRibbonButton CommandParameter="AutoFit"
                                                 telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeTableColumnsLayoutModeCommand}"
                                                 Size="Medium"
                                                 SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/AutoFItToWindow.png"
                                                 Text="AutoFit to Window" />
                        <telerik:RadRibbonButton CommandParameter="Fixed"
                                                 telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeTableColumnsLayoutModeCommand}"
                                                 Size="Medium"
                                                 SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/FixedColumnWidth.png"
                                                 Text="Fixed Column Width" />
                    </StackPanel>
                </telerik:RadRibbonDropDownButton.DropDownContent>
            </telerik:RadRibbonDropDownButton>
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Alignment">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                </Grid.RowDefinitions>
                <telerik:RadToggleButton Grid.Column="0"
                                         CommandParameter="Left,Top"
                                         telerik:ScreenTip.Description="Align text to the top left corner of the cell."
                                         IsTabStop="False"
                                         IsBackgroundVisible="False"
                                         Padding="2"
                                         Grid.Row="0"
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding TableCellContentAlignmentCommand}"
                                         telerik:ScreenTip.Title="Align Top Left">
                    <Image Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/LeftTopCellAlignment.png"
                           Stretch="None" />
                </telerik:RadToggleButton>
                <telerik:RadToggleButton Grid.Column="1"
                                         CommandParameter="Center,Top"
                                         telerik:ScreenTip.Description="Center text and align it to the top of the cell."
                                         IsTabStop="False"
                                         IsBackgroundVisible="False"
                                         Padding="2"
                                         Grid.Row="0"
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding TableCellContentAlignmentCommand}"
                                         telerik:ScreenTip.Title="Align Top Center">
                    <Image Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/CenterTopCellAlignment.png"
                           Stretch="None" />
                </telerik:RadToggleButton>
                <telerik:RadToggleButton Grid.Column="2"
                                         CommandParameter="Right,Top"
                                         telerik:ScreenTip.Description="Align text to the top right corner of the cell."
                                         IsTabStop="False"
                                         IsBackgroundVisible="False"
                                         Padding="2"
                                         Grid.Row="0"
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding TableCellContentAlignmentCommand}"
                                         telerik:ScreenTip.Title="Align Top Right">
                    <Image Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/RightTopCellAlignment.png"
                           Stretch="None" />
                </telerik:RadToggleButton>
                <telerik:RadToggleButton Grid.Column="0"
                                         CommandParameter="Left,Center"
                                         telerik:ScreenTip.Description="Center text vertically and align it to the left side of the cell."
                                         IsTabStop="False"
                                         IsBackgroundVisible="False"
                                         Padding="2"
                                         Grid.Row="1"
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding TableCellContentAlignmentCommand}"
                                         telerik:ScreenTip.Title="Align Center Left">
                    <Image Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/LeftMiddleCellAlignment.png"
                           Stretch="None" />
                </telerik:RadToggleButton>
                <telerik:RadToggleButton Grid.Column="1"
                                         CommandParameter="Center,Center"
                                         telerik:ScreenTip.Description="Center text horizontally and vertically within the cell."
                                         IsTabStop="False"
                                         IsBackgroundVisible="False"
                                         Padding="2"
                                         Grid.Row="1"
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding TableCellContentAlignmentCommand}"
                                         telerik:ScreenTip.Title="Align Center">
                    <Image Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/CenterMiddleCellAlignment.png"
                           Stretch="None" />
                </telerik:RadToggleButton>
                <telerik:RadToggleButton Grid.Column="2"
                                         CommandParameter="Right,Center"
                                         telerik:ScreenTip.Description="Center text vertically and align it to the right side of the cell."
                                         IsTabStop="False"
                                         IsBackgroundVisible="False"
                                         Padding="2"
                                         Grid.Row="1"
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding TableCellContentAlignmentCommand}"
                                         telerik:ScreenTip.Title="Align Center Right">
                    <Image Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/RightMiddleCellAlignment.png"
                           Stretch="None" />
                </telerik:RadToggleButton>
                <telerik:RadToggleButton Grid.Column="0"
                                         CommandParameter="Left,Bottom"
                                         telerik:ScreenTip.Description="Align text to the bottom left corner of the cell."
                                         IsTabStop="False"
                                         IsBackgroundVisible="False"
                                         Padding="2"
                                         Grid.Row="2"
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding TableCellContentAlignmentCommand}"
                                         telerik:ScreenTip.Title="Align Bottom Left">
                    <Image Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/LeftBottomCellAlignment.png"
                           Stretch="None" />
                </telerik:RadToggleButton>
                <telerik:RadToggleButton Grid.Column="1"
                                         CommandParameter="Center,Bottom"
                                         telerik:ScreenTip.Description="Center text and align it to the bottom of the cell."
                                         IsTabStop="False"
                                         IsBackgroundVisible="False"
                                         Padding="2"
                                         Grid.Row="2"
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding TableCellContentAlignmentCommand}"
                                         telerik:ScreenTip.Title="Align Bottom Center">
                    <Image Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/CenterBottomCellAlignment.png"
                           Stretch="None" />
                </telerik:RadToggleButton>
                <telerik:RadToggleButton Grid.Column="2"
                                         CommandParameter="Right,Bottom"
                                         telerik:ScreenTip.Description="Align text to the bottom right corner of the cell."
                                         IsTabStop="False"
                                         IsBackgroundVisible="False"
                                         Padding="2"
                                         Grid.Row="2"
                                         telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding TableCellContentAlignmentCommand}"
                                         telerik:ScreenTip.Title="Align Bottom Right">
                    <Image Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/RightBottomCellAlignment.png"
                           Stretch="None" />
                </telerik:RadToggleButton>
            </Grid>
        </telerik:RadRibbonGroup>
    </telerik:RadRibbonTab>
    <telerik:RadRibbonTab ContextualGroupName="TableTools"
                          Header="Design">
        <telerik:RadRibbonGroup Header="Table Style Options">
            <telerik:RadCollapsiblePanel>
                <CheckBox Content="Header Row"
                          telerik:ScreenTip.Description="Display special formatting for the first row of the table."
                          Margin="2"
                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleTableLookFirstRowOptionCommand}"
                          telerik:ScreenTip.Title="Header Row" />
                <CheckBox Content="Total Row"
                          telerik:ScreenTip.Description="Display special formatting for the last row of the table."
                          Margin="2"
                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleTableLookLastRowOptionCommand}"
                          telerik:ScreenTip.Title="Total Row" />
                <CheckBox Content="Banded Rows"
                          telerik:ScreenTip.Description="Display banded rows, in which even rows are formatted differently from odd rows.&#10;&#10;This banding can make tables easier to read."
                          Margin="2"
                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleTableLookRowBandingOptionCommand}"
                          telerik:ScreenTip.Title="Banded Rows" />
                <CheckBox Content="First Column"
                          telerik:ScreenTip.Description="Display special formatting for the first column of the table."
                          Margin="2"
                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleTableLookFirstColumnOptionCommand}"
                          telerik:ScreenTip.Title="First Column" />
                <CheckBox Content="Last Column"
                          telerik:ScreenTip.Description="Display special formatting for the last column of the table."
                          Margin="2"
                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleTableLookLastColumnOptionCommand}"
                          telerik:ScreenTip.Title="Last Column" />
                <CheckBox Content="Banded Columns"
                          telerik:ScreenTip.Description="Display banded columns, in which even columns are formatted differently from odd columns.&#10;&#10;This banding can make tables easier to read."
                          Margin="2"
                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleTableLookColumnBandingOptionCommand}"
                          telerik:ScreenTip.Title="Banded Columns" />
            </telerik:RadCollapsiblePanel>
        </telerik:RadRibbonGroup>
    </telerik:RadRibbonTab>
    <telerik:RadRibbonTab ContextualGroupName="HeaderFooterTools"
                          Header="Design"
                          Width="140">
        <telerik:RadRibbonGroup Header="Insert">
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Insert the current date or time into the current document."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/InsertDateTime.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowInsertDateTimeDialogCommand}"
                                     Size="Large"
                                     Text="Date & Time"
                                     telerik:ScreenTip.Title="Insert Date and Time" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Insert page numbers into the document."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/InsertPageNumber.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding InsertPageFieldCommand}"
                                     Size="Large"
                                     Text="Page Number"
                                     telerik:ScreenTip.Title="Insert Page Number" />
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Insert block containing formatted programming source code."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/CodeBlock.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ShowCodeFormattingDialogCommand}"
                                     Size="Large"
                                     Text="Code"
                                     telerik:ScreenTip.Title="Insert Code Block" />
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Navigation">
            <StackPanel>
                <telerik:RadRibbonToggleButton telerik:ScreenTip.Description="Link to the previous section so that nthe header and footer in the current section contain the same content as in the previous section."
                                               telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleHeaderFooterLinkToPreviousCommand}"
                                               Size="Medium"
                                               SmallImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/LinkToPreviousHeaderFooter.png"
                                               Text="Link to Previous"
                                               telerik:ScreenTip.Title="Link to Previous" />
            </StackPanel>
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Options">
            <StackPanel>
                <CheckBox Content="Different First Page"
                          telerik:ScreenTip.Description="Specify a unique header and footer for the first page of the document."
                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleDifferentFirstPageHeaderFooterCommand}"
                          telerik:ScreenTip.Title="Different First Page" />
                <CheckBox Content="Different Odd & Even Pages"
                          telerik:ScreenTip.Description="Specify that odd-numbered pages should have a different header and footer from even-numbered pages."
                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ToggleDifferentOddAndEvenPagesHeaderFooterCommand}"
                          telerik:ScreenTip.Title="Different Odd & Even Pages" />
            </StackPanel>
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Position">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>
                <Image Grid.Column="0"
                       Grid.Row="0"
                       Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/HeaderFromTop.png"
                       Stretch="None"
                       VerticalAlignment="Center" />
                <TextBlock Grid.Column="1"
                           Grid.Row="0"
                           Text=" Header from Top: "
                           VerticalAlignment="Center" />
                <telerik:RadNumericUpDown Grid.Column="2"
                                          telerik:ScreenTip.Description="Specify the height of the header area."
                                          IsInteger="true"
                                          Minimum="0"
                                          NullValue="48"
                                          Grid.Row="0"
                                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeSectionHeaderTopMarginCommand}"
                                          telerik:ScreenTip.Title="Header Position from Top" />
                <Image Grid.Column="0"
                       Margin="0 1 0 0"
                       Grid.Row="1"
                       Source="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/FooterFromBottom.png"
                       Stretch="None"
                       VerticalAlignment="Center" />
                <TextBlock Grid.Column="1"
                           Margin="0 1 0 0"
                           Grid.Row="1"
                           Text=" Footer from Bottom: "
                           VerticalAlignment="Center" />
                <telerik:RadNumericUpDown Grid.Column="2"
                                          telerik:ScreenTip.Description="Specify the height of the footer area."
                                          IsInteger="true"
                                          Margin="0 1 0 0"
                                          Minimum="0"
                                          NullValue="48"
                                          Grid.Row="1"
                                          telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ChangeSectionFooterBottomMarginCommand}"
                                          telerik:ScreenTip.Title="Footer Position from Bottom" />
            </Grid>
        </telerik:RadRibbonGroup>
        <telerik:RadRibbonGroup Header="Close">
            <telerik:RadRibbonButton telerik:ScreenTip.Description="Close the Header and Footer Mode."
                                     LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/ExitHeaderFooterEditMode.png"
                                     telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding ExitHeaderFooterEditModeCommand}"
                                     Size="Large"
                                     Text="Close Header and Footer"
                                     telerik:ScreenTip.Title="Close Header and Footer" />
        </telerik:RadRibbonGroup>
    </telerik:RadRibbonTab>
</telerik:RadRichTextBoxRibbonUI>

Again, this is a hard to duplicate bug as it doesn't happen every time.  Any assistance is greatly appreciate and other information is needed please ask. 

[Mihail]

Hello Michael,

Unfortunately we were unable to reproduce the described issue and are unaware of similar problems. If you find a stable procedure to reproduce the problem we will be happy to investigate and fix it. 

Let us know if you have additional feedback.

Regards,
Mihail
Telerik