Hello,
I have purchased a 5" 800x480 touch screen along with the shield and an Ardiuno Mega R3 2560 from Sainsmart.com.
Sainsmart provided the docs and a few example sketches. The simple ones like the screen test program and the touch screen calibration (and I have edited the UTouchCD.h as instructed with the updated values) work, but any sketch that requires touching a button or the paint/draw program don't respond well. Touching the screen produces random results, i.e. if the button is in the upper left corner of the screen, sometimes touching the lower right corner or bottom center of the screen will activate it. However actually touching the displayed button will do nothing.
It's driving me and my programmer bonkers.