Firefox 3 browser hangs when trying to load Sun Secure Global Desktop (SSGD) login applet as well as the Molecule Viewer 3 demo applet on Windows. The customer first observed hangs with 5u23. No hangs were seen with 5u22 and earlier. Initially it was suspected that this issue was a result of CR 6906977. However the customer tried an IDR built with 5u24 and the bug fix for CR 6906977 and still observed the hangs.

I've tested 5u25 internally and it does show improvement, but I observe intermittent hangs. I estimate I observe a hang 1 out of every 10 times I try to access the applet. I also find they seem to occur more frequently when I try from a newly opened browser session. I tested using Firefox 3.5.9 on Windows XP SP3.

I was accessing the Molecule Viewer (Example 3) demo from:

http://java.sun.com/applets/jdk/1.4/demo/applets/MoleculeViewer/example3.html

Steps on how to access an SSGD demo and how to observe the hang, can be found in the comments section.
Havr tried debug with windbg.
Java_sun_awt_windows_WEmbeddedFramePeer_create+0x57 [../../../src/windows/native/sun/windows/awt_Frame.cpp
and
awt!AwtComponent::_RequestFocus+0xd8 [../../../src/windows/native/sun/windows/awt_Component.cpp @ 6385]
awt!AwtToolkit::SyncCall+0x98 [../../../src/windows/native/sun/windows/awt_Toolkit.cpp @ 1314]
awt!Java_sun_awt_windows_WComponentPeer__1requestFocus+0x80 [../../../src/windows/native/sun/windows/awt_Component.cpp @ 7032]

As from the debug find the requestFocus is not getting the focus from WM_SETFOCUS message.

We need some more invetigation on this.