I've just updated to Leopard 10.5.3 and on re-starting my virtual machines (running XP Pro) the display is having real problems updating correctly. I am getting strips of updated screen and flickering sections and strips. It's hard to make out what I have pressed and what's going on. Same problems after a re-start of the virtual machine, but after a few minutes the display seems to settle down. I'll keep monitoring to see if the problem returns.