Touchscreen falsly registering multiple taps on single tap Half of the times my phone's capacitive touchscreen works fine, but the other half it registers multiple taps on a normal tap or on a long-press.

This malfunction happens much more often when the phone is operated while laying flat on the table (i.e. not hand-held). 

When a human body part, like the palm of a hand in a normal operation scenario, is resting firmly against the back of the device the problems usually goes away. 

I'd think this somehow has to do with the so called "parasitic capacitive coupling problem".

Is this something characteristic of capacitive touchscreens in general?

Can it possible be fixed by tweaking some timing parameters in the touchscreen driver settings?
A common fix for this kind of problem is usually buying a case for your phone.

I also have this problem in Galaxy Mini, but ever since I bought a thick silicon case, my problem is solved. But this did not get rid of the misbehaving touchscreen while charging problem, which is probably caused by the flux of electricity messing with the capacitive display.