If you try the shortcut, the code editor must be in focus. Sorry, I got that wrong earlier! That gif uses a slightly older version of Cabbage, the gear cog has been replaced I think with a new icon.
Just hit Ctrl+S. Saving an instrument takes you back to ‘performance’ mode. FWIW, here I can hit the pencil and rule icon again to move back out of edit mode? I will try later on Windows. Btw, what version of Cabbage are you using?