E.g. bug 136596 discusses missing language property. The problem is that any complex property (containing a struct) that is not handled explicitly (only border is ATM) is silently discarded in svx::sidebar::GetPropertyValues. For such properties, we should still show at least a stub, like > Some Property <struct> which would be informative both in the sense that user would see that it's present/defined at this level, and in the sense that it will be clear what is TODO yet (to process specially and display useful value).
This is fair, but also a bit tricky, because I see unhandled entries like this under Direct Formatting even with a completely empty document: - List Auto Format, - List Id, - List Label String, - Para Chapter Numbering Level, - Text Paragraph.