In some window managers (I believe KWin is one of them) the user is able to initiate a drag-and-drop operation, then press alt-tab to raise a window that will the be drop target, and only then release the mouse button so that the drag-and-drop is performed. This is not possible with Metacity, Beryl, Compiz or Xfwm. It is unclear to me whether this is a limitation of the window manager or some other part of the system.
In some window managers (I believe KWin is one of them) the user is able to initiate a drag-and-drop operation, then press alt-tab to raise a window that will the be drop target, and only then release the mouse button so that the drag-and-drop is performed. This is not possible with Metacity, Beryl, Compiz or Xfwm. It is unclear to me whether this is a limitation of the window manager or some other part of the system.