Comment 6 for bug 778765

I can confirm this on UGR (Natty amd64). The + and - buttons are grayed out in both Printers and Keyboard (Shortcuts) applets effectively not allowing the user to add or remove keyboard shortcuts or printers. Now as far as my printer goes, UGR picked it up and automatically configured it as soon as I turned it on so I did not have to add it manually but that doesn't mean the buttons should be non-operational, you should be able to add or remove one manually. Same goes for keyboard shortcuts. Currently you can't even delete an existing keyboard shortcut.

Initially I thought it might have been a problem with permissions in that it might have required authorization before adding/removing a printer as well as a keyboard shortcut but was somehow overlooked by the Gnome3-team. But starting 'gnome-control-center as root didn't accomplish anything, the + and - buttons in both Printers and Keyboard were still grayed out.

That being said, I was able to set/edit existing keyboard shortcuts by highlighting any particular existing keyboard shortcut and hitting the <space> bar. This changes the existing shortcut (or 'Disabled', etc) to "New shortcut". At this point I can hit the key combo I want to set for that shortcut and it will add that key combo as the new shortcut. However, this works only for existing, default keyboard shortcuts. So far I can't find a way to add new shortcut via the + button or remove an existing, default shortcut (which makes sense in a way). Not exactly what you might call a "easily discoverable" feature.