Comment 5 for bug 382843

I am using Gnome-Do, in "Docky" mode. I think you might be onto something there - the effect I described happens below a certain point on the screen, no matter where the window is (ie, if the window's high up, you can drag/drop to any part of it, if it's low down, you can't drop onto it at all). And if I close Gnome-Do then I can drag/drop to any part of the screen.

Well done, I think you've found the problem! I have changed the bug details to mention the gnome-do package as well.