no, not tried on other os/hw yet.
for trying with gui disabled, it's hard to say. since my game's input comes from twl, not from jPCT's keymapper.
* I have a command line switch which directly loads a level at the very start. flickering also happens then with same simptoms, without switching video mode, but only at initial rotation.
* I've tried binding a key to switch video mode without gui. never happened in my trials. gui displaying enabled or not. not sure murphy or?