So, found out while trying to VNC into my work box, that the “Visual Effects” in Ubuntu breaks the built-in GNOME VNC server – what happens is you can input text, click on controls, but changes are not refreshed into the view (the view isn’t “Damaged”). The current workaround seems to be either moving back to Metacity or some other WM, or turning off visual effects.
Side Note: Jolly’s Fast VNC is an AWESOME VNC client – as it suggests, fast, and with a really cool zoom mode for handling well larger screens over VNC, much recommended (after you fix the compositing 😉 )
“Fixed” this by switching from the built-in GNOME VNC client to NX Server/Client from http://nomachine.com/. On the one hand – not really opensource. On the other hand – works great and blazingly fast. Well, I do use the NVIDIA drivers…