It's not very easy to notice it at beginning, but there is easy way of testing it - open xvkbd, terminal, and try to write something, by taping on virtual keyboard. Tap any letter, then, without touching screen any more, wait for a while. In my case, letter auto-repeat, just because cursor is still "over" letter on vkb. Sulu, could You check, if it also happens in Your case? Any way, ideas what may be causing this, anyone?
On 2 devices that I've tested, it works flawlessly - 100% of times - by tapping every edge of the screen. 4 panels are 100% possible - it's just me, who use 2 panels and still have much free space on them - my invention on filling it with content seems small