I’m running XEmacs (v 20.4) under Linux and I have a PC-style keyboard with the Print Screen, Scroll Lock, Pause/Break, Insert, Home, Page Up, Delete, End, Page Down keys, and some of them actually do useful stuff. “Insert” toggles overwrite-mode, “Page Up” actually moves up a screen, etc. The arrow keys are in upside-down-T formation below these keys.
Every once in a while, when aiming for the arrow keys, I manage to mash multiple buttons and screw up the active Emacs window, so that I get a bunch of left-pointing arrow symbols (the ones that normally show a line is being wrapped) at the far left, and the window is blank otherwise. I can’t fix it, except to switch to another buffer and back in that window. The buffer contents aren’t affected, luckily.
It’s a minor annoyance, but I haven’t been able to reproduce it either by hitting keys individually (they either work or produce a harmless error) or by scientifically trying out combinations. I wonder if anyone knows what’s up?