The Case of the Mysterious White Box

[teacherguy]

No idea what the heck I did, but suddenly my stack is exhibiting a very odd behavior. A "white box" goes visible and then invisible, just to the right of center at the top of my stack. It shows itself at almost any action: Hovering over buttons, going to a new card, even clicking the menubar or hovering over tools in the palette. Weirdest thing. And the behavior is transferring to my standalone builds.

Showing invisible items does not make it show, so I don't think it is a field or anything like that. Nothing showing up in the Message Watcher.

Thoughts?

[teacherguy]

Short screencast of the problem here http://dl.dropbox.com/u/1217366/Screeny ... 5%20PM.mov.

[teacherguy]

Another clue: I moved the stack to the right (horizontally) a bit on my desktop to see if the white box would continue to show in the same relative location. No, it stayed in the exact same location relative to my screen, not the stack. Hm, so I moved my stack down vertically with what might about out of range. Sure enough, now that white box does not appear at all. I dragged the stack up again, near the menubar. Once again I get this flickering box to show when I hover over buttons or press something in the menubar.

[teacherguy]

Restarted computer....white box seems to have gone away.