What have you done for trouble-shooting so far?
Restoring Preferences after making sure all customized presets like Actions, Patterns, Brushes etc. have been saved might be a good starting point:
What are your Performance Preferences settings?
I tried restoring preferences, but no change. As for Performance preferences, I had them on default, (memory usage; 70%, Cache; 4,) but also tired changing memory usage to (85%) and increased Cache Levels to 8. Unfortunately the problem persists. Any other suggestions I can try? Thanks for you time and efforts.
If you use a tablet can you try disconnecting it to see if it also afflicts the mouse or trackpad?
I have this issue too — for me it happens when I switch from photoshop to pull up finder or the internet.
it helps to open a new file then the tools there work and in turn work on the original, but I haven’t figured out a way to fix them besides that :/