Visible Range Changed weird behavior

[Amige]

I have a ScheduleView control and I am using a GroupHeaderContentTemplateSelector and a ResourceTypeCollection to display 3 groups:

<scheduleView:ResourceTypeCollection x:Key="ResourcesTypes">
    <scheduleView:ResourceType Name="Schedule">
        <scheduleView:Resource ResourceName="ScheduleOrder" DisplayName="Orders" />
        <scheduleView:Resource ResourceName="ScheduleHeat" DisplayName="Heats" />
        <scheduleView:Resource ResourceName="ScheduleTundish" DisplayName="Tundishes" />
    </scheduleView:ResourceType>
</scheduleView:ResourceTypeCollection>

 

<localStyles:CustomGroupHeaderContentTemplateSelector x:Key="CustomGroupHeaderContentTemplateSelector">
    <localStyles:CustomGroupHeaderContentTemplateSelector.HorizontalTemplate>
        <DataTemplate>
            <ContentPresenter Content="{Binding FormattedName}" Margin="2" Width="80" Height="30" VerticalAlignment="Center"/>
        </DataTemplate>
    </localStyles:CustomGroupHeaderContentTemplateSelector.HorizontalTemplate>

    <localStyles:CustomGroupHeaderContentTemplateSelector.VerticalTemplate>
        <DataTemplate>
            <telerik:LayoutTransformControl VerticalAlignment="Center">
                <telerik:LayoutTransformControl.LayoutTransform>
                    <RotateTransform Angle="0" />
                </telerik:LayoutTransformControl.LayoutTransform>
                <ContentPresenter Content="{Binding FormattedName}" Margin="5" Width="70"/>
            </telerik:LayoutTransformControl>
        </DataTemplate>
    </localStyles:CustomGroupHeaderContentTemplateSelector.VerticalTemplate>

    <localStyles:CustomGroupHeaderContentTemplateSelector.HorizontalResourceTemplate>
        <DataTemplate>
            <ContentPresenter Content="{Binding Name.DisplayName}" Margin="2" Width="80" Height="30" VerticalAlignment="Center"/>
        </DataTemplate>
    </localStyles:CustomGroupHeaderContentTemplateSelector.HorizontalResourceTemplate>

    <localStyles:CustomGroupHeaderContentTemplateSelector.VerticalResourceTemplate>
        <DataTemplate>
            <telerik:LayoutTransformControl VerticalAlignment="Center">
                <telerik:LayoutTransformControl.LayoutTransform>
                    <RotateTransform Angle="0" />
                </telerik:LayoutTransformControl.LayoutTransform>
                <ContentPresenter Content="{Binding FormattedName}" Margin="5" Width="60" Height="23" MaxHeight="23" MinHeight="23"/>
            </telerik:LayoutTransformControl>
        </DataTemplate>
    </localStyles:CustomGroupHeaderContentTemplateSelector.VerticalResourceTemplate>

</localStyles:CustomGroupHeaderContentTemplateSelector>

<scheduleView:RadScheduleView x:Name="scheduleViewOrders" Grid.RowSpan="2"
                              BorderThickness="0 1 1 1"
                              MinAppointmentHeight="20"
                              FirstVisibleTime="00:00"
                              GroupHeaderContentTemplateSelector="{StaticResource CustomGroupHeaderContentTemplateSelector}"
                              AppointmentItemContentTemplate="{ StaticResource AppointmentTemplate}"
                              ResourceTypesSource="{StaticResource ResourcesTypes}"
                              ShowAppointmentDeleteButton="False"
                              ShowCurrentTimeIndicator="False"
                              HorizontalScrollBarVisibility="Visible">
    <scheduleView:RadScheduleView.ActiveViewDefinition>
        <scheduleView:DayViewDefinition GroupFilter="{Binding GroupFilter}" Orientation="Horizontal" VisibleDays="10" MinorTickLength="1h"
                                        MajorTickLength="1h" MinTimeRulerExtent="3000"/>
    </scheduleView:RadScheduleView.ActiveViewDefinition>
    <scheduleView:RadScheduleView.GroupDescriptionsSource>
        <scheduleView:GroupDescriptionCollection>
            <scheduleView:DateGroupDescription></scheduleView:DateGroupDescription>
            <scheduleView:ResourceGroupDescription ResourceType="Schedule" />
        </scheduleView:GroupDescriptionCollection>
    </scheduleView:RadScheduleView.GroupDescriptionsSource>
</scheduleView:RadScheduleView>

 

Now, the problem that I have is next: when I start the application there is no information to display (Image1), then I select a different day, where there is information, but something weird is happening, I can see only one row, the groups have disappeared along with the days (Image2) only after I scroll a little bit everything goes back to normal (Image3).

I am not sure what is happening, have you seen this behavior before?