FX runtime build : http://jfx.sfbay.sun.com/hudson/job/presidio/219/label=windows-i586-14/artifact/artifacts/bundles/release/javafx-2.0-beta-windows-i586.exe (b38)
JRE build : jdk7-b147

It has been noticed that when primary stage of an applet is made full screened then open pressing ALT+TAB is making it to exit it out of full screen mode. Same issue/behavior is not noticed by running the same scenario as jnlp application or standalone application. Also with applet issue is not seen with secondary stage

Steps to reproduce:
1) Install above mentioned jre and fx runtime
2) try to load following applet
http://sqeweb.sfbay.sun.com/deployment1/deployment_6_UR_int_exec_ws/6/deployment/src/javafx/fxfeaturesTest/fxfeaturesTest/html/FullscreenTest.html
3) Click on "Toggle fullscreen" button inside the stage embedded within the browser(primary stage)
4) make sure that stage is getting full screened
5) Now press alt-tab to bring browser window to focus
6) If stage is getting out of full screen mode then bug is reproduced