pref-fonts.js, function selectLanguage: The fetching of the fixed/var font sizes is inside a block if (selectedItem) whereas selectedItem refers to the selected font. This does not make sense because the font size is not bound to the selected font name. The lines var sizeVarVal = parent.hPrefWindow.pref.GetIntPref(...); var sizeFixedVal = parent.hPrefWindow.pref.GetIntPref(...); are totally independend of the selected font.
Submitted thrice. *** This bug has been marked as a duplicate of 47092 ***
verified dup of bug 47092 "Logic Error in pref-fonts.js"
duplicate due to line problems while submitting.