A lot of sidebar UI files have been created, but they have not been added to helpcontent as places to show extended help. Because of this the extended help usually shows up only for uno commands in the sidebar, and not for dropdowns etc. defined in .ui files.
Let's set to NEW.
Dear Gabor Kelemen, This bug has been in ASSIGNED status for more than 3 months without any activity. Resetting it to NEW. Please assigned it back to yourself if you're still working on this.