If I drag anything, like a Dock icon, when I let go of my mouse button the icon won’t drop. The same thing happens when dragging files in Finder, Forklift, tabs in Firefox, songs in iTunes, anything really.

I had this happen a few days ago, but I only noticed it with the Dock. I ran the killall command for the Dock in Terminal about 7 times and it quit misbehaving.

This is a very strange and annoying behavior that I would love to know how to solve.