Comment 21 for bug 1292290

I just recently had this problem. I was trying to clear the default keyboard shortcuts for adding and removing workspaces, which were Alt+Insert and Alt+Delete for me.

Specifically, my problem was that whenever I cleared them, and logged and logged back in they would regenerate themselves. In fact, even if I had set anther keyboard shortcut the original ones would still work even though they wouldn't be shown in the settings manager or the ~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-keyboard-shortcuts.xml.

To fix it, I opened a terminal and ran xfce4-settings-editor. In this gui, I went to the xfce4-keyboard-shortcuts channel. In there I saw entries for Alt+Insert and Alt+Delete, and these entries showed they were mapped to adding and removing workspaces respectively. I double-clicked on them and changed the mapping so that the value field was the empty string. Then I was able to assign hotkeys and log out and log back in normally and everything worked.