For some reason, Thunderbird's new mail notifications are no longer appearing at the top right of my screen. I hear the pop sound of new messages, and Unity's Thunderbird icon receives a red number indicating the number of new messages.
But no Ubuntu notifications at all.
This seems to have happened after my latest series of updates.
Other notifications are working, however.
There was some package in earlier 10.10 that made mozzila notifications show up in ubuntu. But when I upgraded it was amongst the removed and unsupported ones.
Sadly, I don't remember the name now.
EDIT: Thunderbird identificator is not compatible with thunderbird 10.02