I had similar PDF problems with an earlier version of FF. The next major upgrade seemed to correct it.
11 has crashed several times.
12 installed yesterday — with a big notice that it didn’t know where this new version came from. [Even Mozilla can’t keep up with its own revsions.]
[Upgrades — no matter what they fix, they also break something else.]
I got that note as well. On Mozilla-”The version of Firefox you are using is unknown. Download new version here.” Yet I already had downloaded FF 12. Sure they will get it corrected via update.
No kidding. One or two upgrades ago, the bookmarking feature in FF changed from being simple and intuitive, to being WTF?
You used to be able to click on 'bookmarks menu', and all of your bookmark folders would display. From there, it was a simple matter to choose which folder to save the new bookmark in - but no more. Now, you get a choice of maybe five recent folders you've used, and that's it.
What really pisses me off, is that someone had to work to degrade that simple and useful feature. Had they simply left it alone, it would have been superior to what they have now.