Firefox 32 learns an old Microsoft trick and decides to be way too helpful. This is how to undo it. It would be nice if Mozilla/Firefox posted this, but they don't. It would be even nicer if they didn't make this choice for you with out your knowledge or at least tossed in a copy of U2's new album.
Most of the time, Firefox as a PDF reader works fine. Unless you want to print reliably, copy and paste, or search. Hey, I work with 400 page PDFs. Search is good. Firefox should not have made this choice. It would not be bad if it was just PDFs in the browser, but it is not. It effects all of your PDFs.
Nice how all of my PDFs are now Firefox Documents. Not!
This is how to undo this
Yes, there are still several million people running XP. Microsoft does not like you and would like it if you upgraded, but they still want $100 for that.
Click on any image to expand it.
p
on the keyboard, you will jump down to the P's and it will go faster.
That should be it. It may take a second or two for the icons to switch.
The process is the same in Windows 7 and 8 with a few subtle changes.
Adobe Reader is a free download from Adobe.com or http://www.adobe.com