Comment 3 for bug 433817

Yes, it's very reproducible on my system. I have gnome-do running in docky mode, and autohide is enabled. Compiz is also running of course. This seems to happen about 50% of the time in the process of dragging an icon from the applications menu into the dock to create a launcher in the dock. It might be worthy to note that when this happens, the gnome-do dock autohides itself just as this "Drag and drop not supported, invalid drag type" error window appears, even though there is nothing being moved to cover the dock that should cause it to autohide, and the icon that I'm dragging and the mouse pointer haven't even reached the vicinity of the dock. I'm guessing maybe this error appears because something causes the dock to autohide itself when it shouldn't and somehow triggers this "invalid drag type" error? I've also seen this error happen, at much lower frequency, when I drag an icon onto the desktop from the applications menu to create a launcher.

I've managed to get out of this hang by using a keyboard shortcut to open up a terminal and then "killall gnome-panel".