my mac doesn't seem to register the zoom in/out pinch properly under safari. the initial zoom in or out will register just fine, but if i try and zoom in or out right after it will not register until i repeat the same gesture again. for example, the first zoom in will register immediately, but when i try and zoom out it will not register the first time so i need to repeat the same zoom out pinch in order for it to work. it's very annoying having to pinch twice to zoom in or out. any help?