Sadly, the Mozilla folk keep making Firefox worse. Each new rapid release (yeah, that insanity continues) creates as many new problems as it resolves.
I have tried several versions of FF, including the standalone portable. They all stink. Many extensions no longer work — because developers got tired of trying to keep up with FF Rapid Release.
I have some FF versions that will not load or save PDF files. Some have problems with Adobe Flash.
On my desktop, I have quite updating FF and Flash. I am stuck with FF15 — but it sort of works better with the add-ons, etc. I also use FF23 portable on my laptop.
Mozilla took a good browser and are continually trying to (and succeeding) in breaking it and turning it into crap.
I agree, but I’ve kept taking the updates in spite of that. Sheesh on me.