If some of your housing control buttons are sticking or are hard to push apply a drop of pure silicone to the exterior of the respective buttons using a toothpick. Place the silicone in the open portion of the button shaft. Work the silicone in by pushing the button several times until it feels loose. It is best the housing is dry before applying the silicone. The below photo is of food grade liquid silicone that can be purchased at some dive shops.