It is a well known problem that applets do not obey the proper z-ordering of HTML elements in the browser. The root cause is that applets are a heavyweight OS-level component and inherently overlay all content underneath them. Flash content can specify wmode="transparent" to attain proper z-ordering support, though there is a performance penalty for doing so. The new Java Plug-In should support a similar parameter though again there might be a performance penalty for doing so.

This RFE is related to 6633275 and it might turn out that the support for that RFE might solve this problem. However it is more likely that the mechanisms in that RFE would need to be adapted in the context of the new plug-in, since it is believed that the browser-side code needs to change to instantiate a windowless plug-in and use alternate mechanisms for drawing. Additionally, it is likely that this support might initially only work on a subset of platforms. It is believed that there is currently no proper support for windowless plugins on X11 platforms in Firefox, although this is being worked on in the plugin-futures Mozilla working group.

This issue was raised recently on the java.net forums:
http://forums.java.net/jive/thread.jspa?threadID=34806&tstart=0
Posted Date : 2008-01-02 03:30:08.0

Bora Ertung from NeuroDNA has pointed out that the following Mozilla bug has some good test cases around z-ordering issues of iframes:

https://bugzilla.mozilla.org/show_bug.cgi?id=381550
Posted Date : 2008-01-18 23:55:09.0

This is a part of windowless plugin effort, which tracked by 6862869
Posted Date : 2009-08-06 14:55:01.0

N/A

First analysis of FF3 offscreen pixmap discloses the current options
of how to share pixmaps between the server and client JVM,
which is essential for this feature.

The offscreen rendering result shall be handled by the browser.

FF3 currently offers 2 path of rendering, the somewhat classic
software rendering path using traditional X11 pixmaps and gdk processing,
or the new Cairo/Glitz OpenGL hw accelerated implementation.

The goal shall be to minimize the 'pixmap' buffer operations
and to let the result be composed using hw acceleration.
The latter shall be possible with the Cairo/Glitz implementation.

More research is todo, especially the verification of the above implementation
on Windows, and of course the IE7 options.
Posted Date : 2008-03-25 13:43:12.0

(from 6797702):
Fixing it will require extensive cross-organizational work between the Java Plug-In and AWT/Swing teams.
*** (#1 of 1): 2009-01-26 15:57:35 EST   xxxxx@xxxxx  
Posted Date : 2009-03-03 18:50:25.0

Please address this issue!  There are many duplicates of this issue because it is still not resolved.  Iframe Shims are a pain in the applet and don't even work in Safari.  

solve it please!!it is anoying for an applet on facebook.
The java script menu and the chat are hidden by the java applet
this bug does not exist
 6862869
thanks

FIx it please!
6862869 does not exist

Bump

This either needs to be re-opened, or 6862869 needs to be added.

The issue described in this bug is critical to Java on the web. Sun / Oracle, PLEASE address this, or at least re-open this bug so people can vote on it.

I've found another bug that seems to describe this one but is still open if anyone would like to vote for it: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6529824