I noticed following unexpected behaviour (both under Windows XP and 2000):

If I turn "Wrap text" on in the Sun Java System Application Server 9 console (a
standard console window also behaves like that) and then go to the very bottom
of the console (which in full of entries after a server start), mouse scrolling
no longer works correctly: if I click on the up button of the scrollbar the
window shortly "blinks" but its content doesn't move. The same happens if I
click in the scrollbar itself. The effect disappears as soon as I deactivate
"Wrap text". The effect doesn't occur if I use the keyboard instead of the
mouse, or if I'm not at the very bottom of the windows or if I move the lift
directly...