I used to be able to switch to iTunes using cmd-tab and press the space bar to pause a song as it was playing. This allowed me to to stop the song quickly when I was interrupted by a phone call.

However, this no longer works. I can only go to the Controls menu item in iTunes and select Controls --> Pause.

I do see that the menu item "Pause" is mapped to "space". When I press the space bar now with iTunes as the "active" application I just hear a tone. Recently I upgraded both Lion and iTunes so I am not quite sure which one stopped this from working properly.

Does anyone know how to get this functionality back?