Description of problem:
No matter which keyboard shortcut I assign to "Launch web browser", it doesn't actually launch it.

Similarly for 'Volume mute', 'Volume down', 'Volume up', 'Search', 'Calculator', and probably others.

Version-Release number of selected component (if applicable):
gnome-shell-3.1.91-2.fc16.x86_64

How reproducible:
100% here

Steps to Reproduce:
1.System Settings -> Keyboard -> Shortcuts
2.Click next to 'Launch web browser', then press a key
3.Now press that key in another context
  
Actual results:
No web browser launched.

Expected results:
Web browser launched.

Additional info:
Some other shortcuts work fine: 'Launch Terminal', the navigation shortcuts, the screenshot shortcuts, 'Show the run command prompt', 'Show the activities overview', the windows shortcuts.