Same problem (this time an error dialog while trying to open a DVD from an installed system).
Funny, a few seconds later another dialog appears, that is visible in the alt-tab sequence (and probably in the task bar, I don't have it displayed right no to check).
Ubuntu 9.04 x64
Same problem (this time an error dialog while trying to open a DVD from an installed system).
Funny, a few seconds later another dialog appears, that is visible in the alt-tab sequence (and probably in the task bar, I don't have it displayed right no to check).