Sorry but I've upgraded to FF 49.0.2 on a W7/64b up-to-date with FP 23.0.0.185 and I see no differences compared to FF 49.0.1... It works fine
So you'll probably reach your grave before Mozilla will investigate on this...
Anyway, if the problem is caused by the new FF interacting with something other, you can uninstall it and find version 49.0.1
here ... you'll have to choose first the directory corresponding to your Operating System, then your language and you'll get a link to an installation program... do that before to remove your browser...
For windows, choose W32/ or W64/ depending on your machine, Linux and Mac users will probably be able to find their own OS...
About always recommanding last version of browser and Flash player to avoid searching a solution, I must say that I'm able to work Elvenar on my old laptop that has XP as OS and is running FF 39.0.3 and FP 19.0.0.185
Windows, Firefox & Flash upgrades mostly intend to solve
security issues... solving "bugs" are the exception...
But okay... if not everyone has an issue, it's probably some local problem...