Can you confirm this happens on Firefox version 1.99+2.0rc2+dfsg-0ubuntu1? and if you can can you please install firefox-dbg and run a debugging backtrace. PLease run the backtrace if this issue is still reproducible.
Can you confirm this happens on Firefox version 1.99+2. 0rc2+dfsg- 0ubuntu1? and if you can can you please install firefox-dbg and run a debugging backtrace. PLease run the backtrace if this issue is still reproducible.