Solved after all: a hardware problem. I swappen thin clients and all was good on the spare one. And on the original one, with a different screen, kb and mouse, the problem appeared again. So it's hardware.
-- On some thin clients, screen is garbled https://launchpad.net/bugs/69024 -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
