In WeekView, when ShowWeekGroupHeaders is set, templating the GroupHeaders with GroupHeaderContentTemplateSelector lead to a rendering issue (see attached files).
In case I forgot something, here is my GroupHeaderContentTemplateSelector definition :
<svcore:GroupHeaderContentTemplateSelector x:Key="_GroupHeaderContentTemplateSelectorKey">
<svcore:GroupHeaderContentTemplateSelector.HorizontalTemplate>
<DataTemplate>
<ContentPresenter MinHeight="16" Margin="4" Content="{Binding FormattedName, Converter={StaticResource UpperCaseStringConverter}}"/>
</DataTemplate>
</svcore:GroupHeaderContentTemplateSelector.HorizontalTemplate>
<svcore:GroupHeaderContentTemplateSelector.VerticalTemplate>
<DataTemplate>
<ContentPresenter Margin="4" MinHeight="16" VerticalAlignment="Top" Content="{Binding FormattedName, Converter={StaticResource UpperCaseStringConverter}}">
<ContentPresenter.LayoutTransform>
<RotateTransform Angle="-90"/>
</ContentPresenter.LayoutTransform>
</ContentPresenter>
</DataTemplate>
</svcore:GroupHeaderContentTemplateSelector.VerticalTemplate>
<svcore:GroupHeaderContentTemplateSelector.HorizontalResourceTemplate>
<DataTemplate>
<Border Background="{Binding Name.DBResource.Color, Converter={StaticResource _SharedStringColorToSolidColorBrushConverterKey}}" Height="60" Margin="2">
<StackPanel Orientation="Vertical" Margin="8">
<TextBlock Foreground="{Binding Name.DBResource.Color, Converter={StaticResource _SharedBackgroundStringColorToForegroundConverterKey}}" FontSize="16" Margin="0" Text="{Binding Name.DisplayName}" />
<TextBlock Foreground="{Binding Name.DBResource.Color, Converter={StaticResource _SharedBackgroundStringColorToForegroundConverterKey}}" FontSize="12" Text="{Binding Name.DBResource.Code}" />
</StackPanel>
</Border>
</DataTemplate>
</svcore:GroupHeaderContentTemplateSelector.HorizontalResourceTemplate>
<svcore:GroupHeaderContentTemplateSelector.VerticalResourceTemplate>
<DataTemplate>
<Border Background="{Binding Name.DBResource.Color, Converter={StaticResource _SharedStringColorToSolidColorBrushConverterKey}}" Width="140" Margin="2">
<StackPanel Margin="8">
<TextBlock Foreground="{Binding Name.DBResource.Color, Converter={StaticResource _SharedBackgroundStringColorToForegroundConverterKey}}" FontSize="16" Margin="-2 3 0 5" Text="{Binding Name.DisplayName}" />
<TextBlock Foreground="{Binding Name.DBResource.Color, Converter={StaticResource _SharedBackgroundStringColorToForegroundConverterKey}}" FontSize="12" Text="{Binding Name.DBResource.Code}" />
</StackPanel>
</Border>
</DataTemplate>
</svcore:GroupHeaderContentTemplateSelector.VerticalResourceTemplate>
</svcore:GroupHeaderContentTemplateSelector>