ISV/Customer with a webtop built on Win32/Internet Explorer but uses
Java Applets and the JavaScript/LiveScript connector to I.E. and the
Microsoft JVM.

With Sun's JRE 1.4.x plugin and Microsoft VM, IE6 is able
to parse the JavaScript code, load the applet, and then
call the applet methods as needed to pop a new browser
frame, then inside the browser, display a small embedded
canvas panel with some text inside.

However, with Netscape 7.1 and Sun's JRE plugin, the browser
simply hangs and the cursor blocks with the watch-icon, but
no new popup window appears and no embedded canvas panel with
text.

In fact, the browser hangs and I must use the task manager
to force-kill the Netscp.exe process.

In further testing, using the JDK1.5 Beta 1 plugin, we see regression.
IE6 with JRE 1.5Beta1 plugin exhibits the same hang as for Netscape 7.1
Reverting back to MS VM and IE6 again works.

The hang can be reproduced on Mozilla 1.4 - 1.6 and Netscape 7.0, Netscape 7.1 on Linux Redhat 8, 9, and Fedora Core 1 using the Sun JRE plug-in in 1.4.x.
The hang also occurs on Solaris/SPARC Netscape 7 with JRE 1.5B1 plugin.