File>Revert (F12) greyed out at random
I'm running a fully updated PS & Win10 x64, and have recently added hitting F12 periodically in my workflow and toggling-last-state to not "lose my bearings" from the original file on my photoedits.
I'm confounded by the fact that at total random, the option is greyed out and unavailable. I can't seem to tie it to any particular state: 8bit vs 16bit, background or regular layer selected, different tools selected, freshly opened file with a couple edits vs one I've been doing for an hour, etc. etc. Sometimes if it's greyed out I can run some random command, undo, and then it's available at the spot it previously wasn't.
Couldn't find anything on any of the forums, anyone got any ideas? Thanks..
