Why can't I delete a directory in Ubuntu One?

When I delete a directory with all its contents in my "Ubuntu One" directory in Nautilus, it doesn't seem to want to sync with the cloud service. If I log into one.ubuntu.com and look, the contents are still there. If I click on the directory under "My Files", then click on the trash icon and confirm the dialog, the directory is never deleted. It contains several subdirectories which I've tried to traverse down to and often times I get the little animated sync that spins forever next to a selected directory.