[dep, 27Jul2007]

  I noticed that with the 1.6.0_01 jdk my Nimbus scrollbar thumbs were
  being misrendered when shortened.

  This problem appears to have been fixed in the 1.6.0_02 bits, but
  remains (albeit in a less severe form) in 1.7.0_ea. See the attached
  sb_thumb7.png.

  With those artifacts out of the way, the end buttons are being
  misdrawn (sb_buttons.png), and grow more mangled as the space they
  are in decreases. This happens in both 6u2 and 7.

  Perhaps more alarming is that this misrendering will "stick" to the
  lower or right button if the window is enlarged again. See
  sb_stain.png.

  Also attached is a simple test program that can be used to reproduce
  these artifacts.
This is a bug with Swing GTK LAF with Nibus GTK theme, not Nimbus swing LAF.