I somehow managed to get the upper part of the floating inspector obscured by the menu bar. Now I can't move it any more, since I can't grab the title part.
I should be able to grab any part of the thing to drag it, not just the title.
Just switch into the expose mode, and drag the window to the right place.
normally, you can only drag de title in every window. I've this problem with different windows sometimes.
If this ever happens to you again, you can get the HUD back into position just by toggling it off and on again (F7 or via the Window menu). Or if you quit and restart Catalyst it should also move the HUD back down.
In the future, we'll make sure you can't get it stuck under there to begin with.