button pad for new Radpower display acting up.

[handlebar]

I installed the Radpower LCD display on my Radmission about 10 days ago. I began having trouble immediately, and it got worse. I thought maybe I didn't always have my thumb squarely on the right button.

Today I used contact cement to stick little rectangles of inner-tube rubber on the key caps so that I can tell by feel that my thumb is squarely on the correct button and that I'm depressing it fully.

All work fine when I'm stationary. When I'm rolling, the up button is erratic. Perhaps half the time, it will fail to shift or double shift. It seems like it could simply be dirt on the contacts, but I don't know how to open the button enclosure to check.

Has anybody serviced the button unit?