As discussed in this thread:
  http://forums.java.net/jive/forum.jspa?forumID=69&start=0

On Windows Vista (multiple machines, video boards),
only with Aero (DWM) enabled, some swing applications
produce rendering artifacts when scrolling or
dragging internal frames. Doesn't happen if Aero
is disabled (even while the application is running)
by selecting "Vista Basic" color theme in the
Appearance dialog.

For example, run this this Substance L&F demo
(note that the look and feel doesn't matter, it's
reproducible with all L&Fs):
  javaws https://substance.dev.java.net/webstart/test.jnlp

Play around with the pane on the left side -
expand/collapse the "tasks". The click at
"List" tab on the right pane, and scroll
the list. The scrolled area then becomes
black or white (depending on laf).

Similar thing happens in the "Desktop" tab - create
a new Internal frame and drag it around - it
produces similar artifacts.
This indicates that the problem is caused
by the copyArea() call.

Interestingly, if the app loses focus and then gains
it back (alt+tab x2) the repainting problems stop until
the task is collapsed/expanded at which point
they appear again.