I have deleted java, installed new 32 and 64 bit java and even gone to 64-bit Waterfox but nothing has solved the problem. I've installed, disabled and re-installed every damn extension.
Please update to Firefox 23, then Reset Firefox Refresh Firefox - reset add-ons and settings
I THINK it's been solved but since it usually occurs when I write a lengthy email (and I can only write so many useless words about what I'm listening to on ITunes) I can't be completely certain .. If it comes back so will I but so far it looks good.