When I click on the home, back, menu, or search button, most of the time they work but they will sometimes not do anything and won't vibrate but then i try again and it works. It seems to be inconsistent or something. It doesn't always do what it is supposed to do. Anyone experience this on their Razr Maxx? Half the time, I am using a charger from my previous Droid Bionic..the voltage is the same...just slight mA difference...can this cause it?