Firefox 3 and Flex Debug Not Working
If you use Firefox as your primary browser for debugging your Flex applications, you may want to read this bug report before you upgrade you browser to Firefox 3…
[#FB-13064] Firefox 3 and Flex Debug Not Working
If you must have the latest and greatest Firefox, you can always use the workaround of debugging with Safari or Internet Explorer!



It’s fine here using FF3 and Player 10 beta, on OpenSuSE.
The thread in the bug report is interesting. If you use FF extensions, I would read the post to see what extensions seem to be causing trouble for the debugger.
Working fine here: Kubuntu 8.04, FF3, Flash debug player 9.0 r124. Sounds like a Windows only problem (go Linux!)
It’s been logged for Mac (unix) and Windows. A bug has now been filed with Mozilla as it appears the problem may be with Firefox.
I found that if you set the wmode to opaque, the debugger works with Firefox 3….
http://www.mostlyflex.com/2008/06/23/firefox3-vs-flex-builder/
You can set it to “transparent” too, it’s working fine for me, as well the “wmode” param is define