gparted will fail mid-operation because of XFCE automounting the drive. This could be a serious problem resulting in filesystem corruption and data loss, depending on whether or not the interrupted operation is recoverable. See Launchpad bug 
https://bugs.launchpad.net/ubuntu/+source/thunar/+bug/1078445

Quotes:

"On startup, gparted ends up causing remove/add events to happen for unmounted partitions. Udisks has some logic in it to NOT auto mount partitions that show up on a disk that itself wasn't just hot plugged to prevent this sort of thing from happening. I guess xubuntu uses something else for auto mounting that isn't quite so smart?"

"This is still a problem in Xubuntu 14.04.1. It can cause gparted to fail mid-operation, e.g. the operation partition resize (which takes the existing filesystem and moves it left and then grows it) will fail immediately after the move left. This leaves the disk in a state where the partition has been expanded, but the filesystem it contains has not, so the filesystem does not fill the partition and needs to be repaired."