Comment 361 for bug 263435

A Google search gleans some interesting information on this bug:

http://www.asserttrue.com/articles/2006/11/17/firefox-and-flash-swf-selection-and-focus-problems
[Stating/showing that issue may be rooted in the wmode attribute]

http://www.ibm.com/developerworks/opensource/library/os-78414-firefox-flash/index.html
[Fully-Functional code workaround in Linux using cnee and Perl, code can be applied to Windows as well]
--"Linux is required, with Firefox V2 or later. The libXnee and cnee components are necessary to monitor systemwide keyboard events, and Perl handles the algorithms. Certain Perl modules are required to process the cnee output and send X Window System events: threads, Thread::Queue, X11:GUITest and Time::HiRes. Although implemented on Linux, the general concepts presented here are applicable to multiple operating platforms, such as Microsoft® Windows®. All that is required is a cnee replacement that can print out systemwide keyboard events reliably, as the Firefox extension and Perl code are cross-platform."

http://wwwx.cs.unc.edu/~gb/wp/blog/2007/06/08/fixing-firefox-flash-foolishness/
[More code, this time using Flash's ExternalInterface object]

The third link provides a .zip containing an example of the code; I have attached it to this bug.