Some of the drop-down menus in the Java2Demo fail to appear on windows platforms using 1.3.1_03b01. So far I have seen it on WinXP home, Win2000 and Win95.
It does not occur for every drop down menu (random). In the Java2Demo app, the drop down menu in the control panel (located to the right) is a good example. Sometimes when a user clicks on the menu a grey outline of the menu selection appears but nothing is filled in inside the box. Leaving the mouse over this area for a long period does not help. However if the user clicks-unclicks and clicks (double click) again on this menu it appears perfectly.
Turn on the tools check-box to produce more drop down menus for the 'inner' applets. On average every ~4th dropdown menu you select will fail on first click (but will work normally on the second click) On the paint demo, drop down menus fail on menus even containing the colour selection on the upper right app of that demo (Paint). I found win95 to give the least number of failures.
These failures do not occur with 1.3.1_02.