Hi i got my tour from my friend he said his wasnt working, turns out it was just a software issue when i upgraded it from 4.7 to 5.0 it was fine... now it wont input trackball wont work, keypad wont work, side buttons, top lock button every effing button... and a couple times it worked but for the most part nope.
Sounds an awful lot like moisture infiltration from some source. Sweat, shower steam, something. It can cause sporadic keyboard and selection problems.