Comment 24 for bug 428509

Another situation in which turning do-not-disturb mode caused of fullscreen application is not appropriate:

I have two monitors at work and three virtual desktops, six spaces total. Normally notification bubble is shown at the left monitor. However, I have VirtualBox in fullscreen mode on the right monitor at the leftmost desktop.

And although notifications bubble isn't overlapped by this fullscreen window, notifications are disabled! Even worse, notifications are still disabled when I switch to another virtual desktop which have no fullscreen applications at all.