Lol, I underdstood the question, u didn't
Miui has support for long press action, cm has press, long press, double tap. He want to change "short" press from open menu to recent, I always did this too on every device that have hardware keys . It's better to have the ability to switch between apps in a fast way rather open a menu when have an emulated button too (yes google has forced menu button appearance )
Sent from my nexus 7