thanks for letting me know.

The limitation with play(held) is that Apple's driver does only send 
a press but no release event for it. Thus, a play(held) press only 
lasts for a couple of milliseconds (as the only alternative would be: 
forever). The same limitation exists for the menu button.

Any other buttons, though, should just be fine and allow you to cycle 
through as many apps as you like.

Hope that helps.

Best regards, 
Felix