Well I can't reproduce this on my laptop but I'll try to
updates-testing and fetch the updates to reproduce this on my desktop.
This can't be reproduced even you do the same update hunk that caused
the issue once shared-mime-info is downgraded.
Maybe someone can install a F18 VM and update from updates-testing to
see if it happens or not.
But I hope that this won't hurt people once the updates from
updates-testing got merged to the updates repository.
Galatasaray University - Computer Engineering Dept.