After upgrading to Firefox 31.0 I have problem typing in using language specific keyboard (PL - Polish Programmer). I set language at the language bar to PL. I can type in Polish fonts in other application like MS Word or Notepad. But as soon as I open Firefox or change focus to one of Firefox tabs the language value on the language bar changes back from PL to EN and I can't type Polish font by pressing Right-Alt (for example Right-Alt + s to type ś). I can copy Polish fonts from other editors and paste to Firefox, I can use check spell to insert correct fonts, but this is not what I want to do. I want to type in Polish fonts straight away. I haven't had this problem in previous version of Firefox. I will not upgrade to version 31.0 on other computers until this problem is fixed.