Touch input does not work right when phone is plugged in Basically touch input either doesn't work at all, or works erratically.  This includes the the lock screen too.  It happens both plugged in to a USB port or to the outlet.

I've had this problem on two phones, and HTC Nexus One and and Samsung Nexus S. 

Does anyone have any idea about what the cause of this and if I can do anything to fix it?  Have you seen this problem?
I had the same problem with the HTC Nexus One and it was directly related to heat. Whenever the phone got too hot the touch screen would flake out. Charging the phone makes it heat up, the worst time for me was when it was in the car dock, heat from charging and from the screen being on all the time. When ever it did this all I had to do was hold it in front of the AC vent for 15 - 30 seconds and the screen would work normally.