I've noticed this glitch for some time, and it seems to be repeatable even after resetting Firefox. First, on a webpage I want to print, I copy a text I want to use as a filename. Then I start a print of the page (menu or ctrl-p), and select "Microsoft XPS Document Writer". It would give the printing message window, and then the Windows' standard "save-as" window to create an XPS-print file. When I try to past the content of my clipboard to the filename field, the edit cursor would stop blinking, and both Firefox (browser and print windows) and the save-as window hangs. "Not Responding" would be stated in the title bar of both the Firefox browser and print-message window, and trying to close either windows would bring up the "Firefox is not responding" window/session. Forcing the program to close would close both the Firefox browser and print window, but the "save-as" window would remain (which would now become responsive but does not have anything to save). Again, I've already tried resetting Firefox, and I've notice this glitch on any computer I use while doing an XPS print from within Firefox. I believe I've been encountering this glitch since prior to version 21.0 of Firefox. I've had no problems with Copy&Paste in any other situations or programs, and no problems using XPS printing (either with copy&paste in other programs, or manually typing in the filename in Firefox). While typing in the filename is a do-able work-around, it is rather annoying and bothersome. To add an interesting twist to this problem, and another work-around, I've found that if I open notepad (or any text editor I suspect) prior to printing, past into notepad, REcopy what is now in notepad, and then start the XPS print, I can now past into the filename field and save the XPS file. Also, RE-copy&paste from notepad works even after starting the print session as long as I've made my first paste into notepad BEFORE starting the print session. Trying to do the first paste into notepad after starting a XPS print would result in nothing pasted into notepad (but also none of the programs/windows would hang either).