I am exploring themes but I am not able to change anything other than the editor window and its contents.
Referring to the docs I should be able to change everything in the sidebar, but nothing works for me when I do this - in fact all themes (even OOB themes) just show a white background. If I change in appearance it will switch between light and dark, but I have no control over anything else that is not the editor
Any ideas what is wrong? Many thanks.