My screen experiences phantom touches where the screen jumps wildly as if being touched and swiped rapidly. Sometimes thus triggers Cortana. It seems as if the back button, windows home button, search button, and sometimes the middle screen lock/unlock button are being triggered simultaneously. This occurs frequently in my pocket. It also correlates with overheating and leads to rapid battery drain.
To alleviate the problem I have to:
1.) One hand grip the device applying pressure at the top of the device between the sim/memory slot and above the volume up button then type with one hand.
2.) Lock, then unlick the screen.
3.) Physically attempt to bend the handset about it's longitudinal axis (in am attempt to relieve the apparent pressure near the search button.
Sometimes this phenomenon is induced while charging and the micro USB cable is wiggled slightly to the left or right (design flaw).