Please let me know what to do/if this is a known problem/if I need to post this somewhere else to get it fixed.
What other apps do you have running at the same time? I've seen stuff like this when a companion app hijacks input. Also, have you tried shifting to another app and shifting back? Does that solve the problem?
I'd like to help you tack this down, but I'm going to need more info. For instance, what OS are you running? And which specific version of Photoshop are you using -- you can check the first line of Help > System Info.
It has been happening on my old iMac, a replacement iMac I recently got and a colleague’s iMac.
When it happens there’s no way to save and the only way out is to force quit Photoshop.
It might happen to me once or twice a week and I haven’t found steps to reproduce it yet.
Let me know if you need any more info. It’s an extremely frustrating problem!
Running the following (although I’ve been experiencing it through previous dot releases)
Photoshop 2017.1.1 20170425.r.252 x64
Running alongside the typical apps: Illustrator, Indesign, Acrobat, 1password, dropbox, Spotify, Safari, Chrome etc.