Today, my Firefox 11 was upgraded to version 12. I held my breath waiting to see if the usual problem of having my RealPlayer Addon be deactivated. Well, it did not this time. Going from FF 9 to FF 10 was good, but I had the problem going to FF 11. I think the version of the Addon makes a difference. So if you have not upgraded to FF 12, please upgrade to RealPlayer 15.0.2 beforehand.