J2SE Version (please include all output from java -version flag):
W:\borsotti\jtest>java -version
java version "1.6.0-beta2"
Java(TM) SE Runtime Environment (build 1.6.0-beta2-b80)
Java HotSpot(TM) Client VM (build 1.6.0-beta2-b80, 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 JScrollPane contains a JPanel whose size matches the
one of the vieport. The JScrollPane scroll policy it set
to display always the horizontal scrollbar.
When the window is maximized, the scrollbars are shown,
but the knob of the horizontal one is not displayed.

Steps to Reproduce (be specific):

Compile and run the attached program. Hit the maximize
button on the window, and see the knob at the bottom.