Photoshop layers snap back to original position

While working on a multi-layered Photoshop document, any layer I tried to move would revert back to its original position. I can't locate any buttons that were inadvertainly enabled. I've also trashed the perfs. Short of reinstalling, I'm stumped.

I love this question. It's one of my all time favorites. You won't believe the answer.

Change your Color Picker from the Apple Color Picker to the Adobe Color Picker. This is in Preferences.

This is in the FAQs by the way.