I have a sample project that uses the RadRichTextBox and RadRichTextBoxRibbonUI controls. I'm using the Office2016 theme with NoXaml binaries. I was referencing the assemblies directly in the install directory:
C:\Program Files (x86)\Progress\Telerik UI for WPF R2 2019\Binaries.NoXaml\WPF45\Telerik.Windows.Themes.Office2016.dll
...and this all worked fine . I've since run the upgrade wizard to bump up to R1 2020 and this moved everything locally in the lib folder. Everything works as before with the exception of the RichTextBox, which does not render (the ribbon and other controls all render fine). If you check Mole you can see the top level element for the RichTextBox but it has no children and the control does not render.
One thing I notice, looking at the R1 2020 version of Office2016.dll in JustDecompile, is that the baml for richtextboxui seems to produce a parser exception:
Current member / type: themes/telerik.windows.controls.richtextboxui.baml
File path: C:\Program Files (x86)\Progress\Telerik UI for WPF R1 2020\Binaries.NoXaml\WPF45\Telerik.Windows.Themes.Office2016.dll
Product version: 2019.1.118.0
Character '0' was unexpected in string '0'. Invalid XAML type name.
at MS.Internal.Xaml.Parser.MeScanner.ResolveTypeName(String longName)
This is not the case for the same baml file in the equivalent R2 2019 assembly, which displays the xaml you'd expect.
Is this a known issue, or am I missing something else?