[OlympicZero]

I don't really understand, so I'll guess. Sounds like the window was moved, try hitting the "F" key and seeing if you can see it in one of the preview modes.

 

[Kaneanite]

Try pressing ctrl-0 (thats a zero, not an O). I know I'm late in posting it, but atleast maybe it'll catch your attention so you can tell us if you've solved it or not. I'm sure you have since you've already made stuff recently.

 

[ChristopheR.]

I think that's the same thing that happens to me.

Go To...

Window > Workspace > Reset Palette Locations.

See if that works