Apprently, the TAB key of my built-in keyboard started to screw up seriously. Not a bid deal since I’m using an external keyword at my offcie, but in order to anticipate any definitive failure, I remapped my right option key to TAB. Not a bad deal after all, since I never use this modification key. Now, for switching between app, I can simply use my two hands: left for ⌘ and right for ⌥ .