I also found that forcing Nautilus to restart by running "killall nautilus" in a terminal will temporarily fix the problem. I don't know if Thunar works the same way but those of you with Xubuntu may want to try this.
I also found that forcing Nautilus to restart by running "killall nautilus" in a terminal will temporarily fix the problem. I don't know if Thunar works the same way but those of you with Xubuntu may want to try this.