Taskboard with ItemTemplate definition, getting error "Both 'ContentTemplate' and 'ContentTemplateSelector' are set"

[Mohamad]

Hi, 
Using Telerik.UI.for.Wpf.NetCore.Xaml  (2022.3.912).
I'm getting an error for the taskboard the first time it loads
Both 'ContentTemplate' and 'ContentTemplateSelector' are set;  'ContentTemplateSelector' will be ignored. RadTaskBoardItem:'RadTaskBoardItem' (Name='')
this error as many as the Item task that appears.

Then when I exit and return to the taskboar page, another error appears:
Cannot find source: RelativeSource FindAncestor, AncestorType='Telerik.Windows.Controls.RadTaskBoard', AncestorLevel='1'

        <telerik:RadTaskBoard x:Name="RadTaskBoard01"  Grid.Row="3" 
                              ItemsSource="{Binding TaskboardCollView}" 
                              GroupMemberPath="State"
                              Background="{StaticResource StripeColor}" 
                              AutoGenerateColumns="False">
            <telerik:RadTaskBoard.DragDropBehavior>
                <localservice:CustomTaskBoardDragDropBehavior/>
            </telerik:RadTaskBoard.DragDropBehavior>
            <telerik:RadTaskBoard.Columns>
                <telerik:TaskBoardColumn GroupName="NEW" Header="Red"  />
                <telerik:TaskBoardColumn GroupName="INPROGRESS" Header="Yellow" />
                <telerik:TaskBoardColumn GroupName="REVIEWED" Header="Gray" />
                <telerik:TaskBoardColumn GroupName="DONE" Header="ForestGreen" />
            </telerik:RadTaskBoard.Columns>
            <telerik:RadTaskBoard.ColumnHeaderTemplate >
                <DataTemplate>
                    <Grid>
                        <Grid.ColumnDefinitions >
                            <ColumnDefinition/>
                            <ColumnDefinition/>
                            <ColumnDefinition/>
                        </Grid.ColumnDefinitions>
                        <Border  Width="17" Grid.Column="0" Background ="{Binding Header}"  BorderThickness="1" BorderBrush="Black" CornerRadius="10" ></Border>
                        <TextBlock Grid.Column="1" Text="{Binding GroupName}"  HorizontalAlignment="Left"  />
                        <TextBlock Grid.Column="2" Margin="10 ,0 ,10, 0" Text="{Binding Items.Count}" HorizontalAlignment="Right" />
                    </Grid>
                </DataTemplate>
            </telerik:RadTaskBoard.ColumnHeaderTemplate>
            <telerik:RadTaskBoard.ItemTemplate>
                <DataTemplate>
                    <Grid >
                        <Grid.ColumnDefinitions >
                            <ColumnDefinition Width="5"/>
                            <ColumnDefinition/>
                        </Grid.ColumnDefinitions>
                        <Grid.RowDefinitions >
                            <RowDefinition/>
                            <RowDefinition Height="25"/>
                        </Grid.RowDefinitions>
                        <Grid Grid.Row="0" Grid.RowSpan="2" Grid.Column ="0" 
                              Background="{Binding CategoryName, Converter={StaticResource CategoryToColour}}">
                        </Grid>
                        <StackPanel  Grid.Row="0"  Grid.Column ="1" >
                            <TextBlock Text="{Binding Parenttitle}"  Margin="15,0,5,0"   Foreground="{StaticResource StripeColor}"  FontSize="16" TextWrapping="Wrap"  />
                            <StackPanel Visibility="{Binding Isparent, Converter={StaticResource BoolToVisible}}">
                                <TextBlock Text="Have Sub Task"
                                           HorizontalAlignment="Right"
                                           Margin="0,0,5,0"
                                           Foreground="Red"
                                           FontWeight="Bold"
                                           FontStyle ="Italic" 
                                           FontSize="12" />
                            </StackPanel>
                            <StackPanel Visibility="{Binding Title, Converter={StaticResource EmptyToVisible }}">
                                <TextBlock Text="{Binding Title}"
                                           Margin="15,0,5,0"
                                           Foreground="Brown"
                                           TextWrapping="WrapWithOverflow"
                                           FontSize="14" />
                            </StackPanel>
                            <TextBlock Text="{Binding Description}"
                                       Margin="15,0,5,0"
                                       TextWrapping="Wrap"
                                       FontSize="14" />
                        </StackPanel>

                        <TextBlock Text="{Binding Assignee}"  Grid.Row="1"   Grid.Column ="1" Margin="15,0,15,0" Foreground="ForestGreen"      
                                   FontSize="16" FontStyle="Italic"  HorizontalAlignment="Right" VerticalAlignment="Bottom" />
                    </Grid>
                </DataTemplate>
            </telerik:RadTaskBoard.ItemTemplate>
        </telerik:RadTaskBoard>

[Stenly]

Hello Mohamad,

This message is shown due to the fact that the RadTaskBoard has an ItemTemplateSelector set by default through its style. In order to remove this message when setting the ItemTemplate, you can set the ItemTemplateSelector property to null, since only one of those properties can be applied at a time:

<telerik:RadTaskBoard x:Name="RadTaskBoard01"  Grid.Row="3" 
                              ItemsSource="{Binding TaskboardCollView}" 
                              GroupMemberPath="State"
                              Background="{StaticResource StripeColor}" 
                              AutoGenerateColumns="False"
			      ItemTemplateSelector="{x:Null}">

Regarding the second inquiry, I was not able to reproduce it on my end. Would it be possible to give the attached sample project a try and let me know if I am missing something?

Regards,
Stenly
Progress Telerik