J2SE Version (please include all output from java -version flag):
  java version "1.6.0-beta2"
  Java(TM) SE Runtime Environment (build 1.6.0-beta2-b82)
  Java HotSpot(TM) Client VM (build 1.6.0-beta2-b82, mixed mode, sharing)

Does this problem occur on J2SE 1.4.x or 5.0.x ? Yes / No (pick one)
  yes

Operating System Configuration Information (be specific):
  Windows XP Professional SP2

Hardware Configuration Information (be specific):
  Intel Pentium III, 730 Mhz, 384 Mb RAM

Bug Description:
  A JFrame contains a JPanel with a JToolbar with a flow layout in it.
  If the frame is resized shrinking it, the toolbar components
  are moved to a second row inside the toolbar, but the size
  of the panel is not recomputed properly.

Steps to Reproduce (be specific):

  Compile and run the attached program. Drag the right border of
  the window to the left, and see that the height of the window
  does not change. The items that have moved to the second row
  are partly hidden.