The text goes nowhere once i select it. This is to say, if I double click a word in a input field, the word disappears, if I try to use Ctrl+A to all the content in a input field, all the letters disappear. This happens occasionally. When this phenomenon is happening, I can't type site address in the address bar, either. I am using Firefox 36.0.3 currently in a updated Arch linux. Add-ons are not relevant because i've tried safe-mode. And I've tried to uninstall, remove all the config file, then reinstall, not working. This happened to one of my mates once, drived him crazy. Never expected this happens to me, 囧. This sucks.