Reply to S4 Browse List button sticks!

I've had the S4 for quite some time now and recently the browse list button on the unit (the small button in the centre for browsing through tracks in an extended list) sticks and I either have to hit the button very hard or 2 or 3 times before it works. It is very annoying and completely messes with my workflow and makes me agitated while DJ'ing. I tried to blow around the button with compressed air but it didn't work. Also I tried mapping midi commands on my keyboard but I like the feel of just using the browse button on the unit? Any ideas??