J2SE Version (please include all output from java -version flag):
java version "1.6.0_11"
Java(TM) SE Runtime Environment (build 1.6.0_11-b03)
Java HotSpot(TM) Client VM (build 11.0-b16, mixed mode, sharing)

Does this problem occur on J2SE 5.0.x or 6.0? Yes / No (pick one)
Yes

Operating System Configuration Information (be specific):
Microsoft Windows XP [Version 5.1.2600]

Bug Description:
Regression: Window dispose() calls hide() instead of setVisible(false)

This is a duplicate of 4328086 and possibly a regression from 1.4 since that bug report claims to have fixed this bug in 1.4 and yet we can see it in 1.6.
Window.java line 994 is calling the deprecated method Window.hide() instead of setVisible(false).