Ubuntu Problems with Firefox 44 and Firefox 45

I am a user of Ubuntu 12.04 x64 almost since its release and i can say that i am very satisfied with it.

But recently i ran into two problems both concerning Firefox which is my main browser.

When Firefox was updated to version 44 i had serious problems with videos and Firefox crashed every time a video was present in the page i visited.

This problem is also mentioned here. I followed the instructions and the problem was fixed until the next update of Firefox where the problem returned. I have also seen this thread and i even found this in Mozilla and submitted my feedback, but unfortunately i had no success in finding a solution.

Of course there are no such problems in the corresponding version in windows which i use for work.

My solution was to use FF43 or, since i plan on upgrading to Ubuntu 16.04 when it is released, i used an extra disk and installed ubuntu 15.10 just to see if i still had such a problem.

The result was that in Ubuntu 15.10 FF was working ok until version 45 in which videos are OK but one of my main add-ons, (x-notifier) stopped working properly to the point that it is unusable. Again the only viable solution for me is to use FF44.

Again, no such problems in the windows versions of FF and my FF profile is always the same.

Now, i am aware that i maybe mixing two separate problems in one post and i apologize if it is so. But as an end user i find it hard to not combine these two, because to me it seems as there is a pattern involving FF and Ubuntu.

As i am planning to upgrade to Ubuntu 16.04 anyway, it is not a big problem for me to wait for a couple of months and in the meantime use FF44 or FF43.

But i am afraid that there will be something wrong with FF and Ubuntu 16.04 also !

If someone is aware of anything that might help it will be great.

Thanks in advance for any feedback submitted, and i am always grateful both to all the people who make these awesome pieces of software and to the people answering questions !