I experienced this problem a few minutes ago and found this post. Then I remembered I wasn't having it until now. After I unplugged the phone from the wall charger it automatically fixed itself. I didn't have this problem with my OTO charger, but with this 3rd party charger.
Since the touch screen is based on a capacitor that measures the electrical input when it comes into contact with our skin, I assumed that the charger caused an improper electrical reading. This may be because of the 3rd party charger is improperly calivrated or the capacitor is having a soft surge due to the charging process.
Can anyone verify the problem that I experienced? Does this happen to all while charging or at random times, too?