During a call, if the phone is held to the ear/cheek, it is very easy for touches to the phone screen to be taken as inputs, causing dial tones, muting, or entering settings, etc. This is even though the screen goes dark due to the proximity sensor, but apparently any touch is still interpreted as input.

How can this be prevented? Currently the only sensible way to use the softphone is to avoid touching the screen at all, but when trying to hear a conversation it is natural to put the earpiece as close to the ear as possible.