After 20 or 30 minutes use the touchscreen both develops unresponsive areas (on stylus and/or finger) and eventually starts triggering random window opening and becomes unusable until left to cool off for a while, restart not necessary.
I'm sure it's a hardware issue as I have restored previous functioning twrp images, also restored a stock rom with user data davlik cache clear.. same problem, it is very interesting to utilize the developer options of "pointer location" or/and show touches as it makes it easy to see exactly what a faulty touchscreen Is reporting! no wonder random windows/menus would start opeining!!
P.S Unfortunately I've rooted the device so may not be able to get a warranty replacement I've searched and so far not found a method for restoring an original non voided bootloader for these devices.. I did however notice some interesting progress for the tegra 3 series though, where someone had worked out how to backup the original bootloader before rooting and then restore it after rooting, so there is hope..... if any devs here want to pursue that for the note 7 here's the link http://forum.xda-developers.com/show....php?t=1927818