A gaming machine cabinet has a cabinet door is pivotally connected thereto and movable between a closed and open positions. A cabinet door button panel includes a panel support surface opposite the door's inner side, a capture structure at a first boundary of a button panel opening, and a blocking structure at a button panel second boundary opposite the first boundary. A button panel base has a first edge received in a button panel frame capture structure, and second edge received on the panel support surface. A locking flange with a locking projection extends from the button panel base lower side, the locking projection moveable between extended and retracted positions. With the button panel base in an operating position, a locking projection may be placed in the extended position to contact the blocking structure and thereby retain the button panel base in the operating position.