PDF Download for Firefox
I've been having the worst time closing a tab in which a PDF was opened in Firefox.
PDF Download solves the problems everyone has about handling PDF files with Firefox. This extension, every time you click on a link, checks if the target is a pdf file and in this case let you choose what you want to do (open pdf file inside or outside Firefox, download it to the filesystem or view it as HTML).
Here's the dialog box that pops up when you click on a link.
UPDATE: It's works great.