Two regression testcases fails from 1.6.0_10 b12 onwards

The following two testcases should display 2 frames when executed. But when run, only one frame is being displayed. The other frame looks as if it is translucent when moved. The frame can be seen in the taskbar.

This happens for builds 1.6.0_10 b12 onwards. It works fine with the previous builds.
This behavioiur is seen in Windows Vista as well as Windows XP Home

1.java/awt/Window/AppletWarning/AppletWarning.sh
2.java/awt/event/HierarchyEvent/UserTest/UserTest.java

In Linux and Solaris the above 2 testcases show one frame with black background from the build 1.6.0_10 b12 onwards and works fine with the previous builds .