I don't really know what is happening, but I think this might be Kwin. I tried removing my firefox profile but it did not help. I removed plasma config files, it didn't help. Everything is OK if I log in as a different user on the same machine. Problem is there is no right-click menu in firefox if I am NOT connected to an external monitor. Everything is normal if I connect external monitor, and the menus display in the right window. I looked in "special application settings" but nothing is ticked off in there. Other apps are fine. Please help.
Linux mint 17 Quiana, KDE 64bit. KDE4.13.3