The previous bug on this train of thought, 4403726, was closed noting that
the JTopLevel class should call setDoubleBuffered(false). Doing this does
indeed allow Swing components to be rendered into JTopLevel w/o trouble.

Still, there is a HeadlessException that can occur from the paint method
if double buffering is turned on. This exception should be documented.

An appropriate test/demonstration is attached to bug# 4403726, so I will not
repeat it here.

In reviewing the code it seems that double buffering isn't truly important
to AWT components, or to lightweights implemented in architectures differing
from the Swing architecture (for example the "LW" components I wrote for
the AWT test team). The Swing components, though, can be double buffered
and it's this code that is at issue because it throws the HeadlessException.
Because of this I'm unclear whether to file this against Swing or AWT.