Maybe I have been there and done that a few more times than you, especially when overlooking all 3 parts of a door lock. If there is no signal thru the lock the control or if the User Interface thinks there is an open circuit, it will beep like that. I suppose you have never tried to enter a command with the door open before?
Also, the dispenser switch is a customary problem area, and you can check it from the top.
You cannot tell if the User Interface is bad simply by examining the buttons and structure. If you could, please come with me on my next service call so I can do without my meter
More likely than not the user interface is bad, but it never hurts to rule out the other 2 first. This is per the Whirlpool Tech line associate I consulted on your behalf.