Please describe the problem:
The Workspace selector allows one to move windows to different workspaces by
dragging rectangular areas in the workspace panel. However, when dragging the
rectangle outside the workspace selector area, the original rectangle disappears
while the window is not moved.

Steps to reproduce:
1. Open a window
2. Click on the associated rectangle in the workspace panel
3. Drag it downwards until the mouse disappears from the screen
4. Release the mouse button


Actual results:
The rectangle disappears from the Workspace applet.

Expected results:
The rectangle should be restored to the original workspace, since the
destination of the "drag" was not valid.

Does this happen every time?
Yes.

Other information:
A similar effect happens in other situations. This seems to be a symptom of a
wrongly coded behavior.