panel-desktop-handler: Add `OnlyShowIn=XFCE` key
When a user logs in to other desktop environments (consequently, without xfce4-panel
), their file manager might show the Create Launcher on the panel menu item, which is useless without a running instance of xfce4-panel
and only leads to error messages and confusion such as these:
Debian & Ubuntu
Adding OnlyShowIn=XFCE;
ensures this action is hidden to other desktop environments.