One should not mix Swing and AWT DnD support for Swing components
(and should not use direct AWT DnD support for Swing components).
An example of issues that are caused by the mixing is described at
http://forums.java.net/jive/thread.jspa?messageID=137339.
Swing should clearly document that one should use Swing DnD
support and shouldn't use AWT DnD support for Swing components.