I’ve only been using Scrivener for about half an hour, so please forgive me if I’m missing something here:
I really like the fullscreen mode that allows me to blank everything else out (full opacity for me), but it seems to break the ctrl+(x) font style shortcuts - ctrl+i is like hitting tab, while ctrl+b/u don’t seem to do anything. The solution for me has been to kick out of fullscreen mode to change font styles, but that’s very inefficient and definitely harms Scrivener’s usability.