Same issue on my Thinkpad X201 (Ubuntu 13.04 64bits). I also noticed that if I click on an entry of the menu bar of any application (for example File menu of Firefox), then use the function buttons to increase/decrease brigthness :
1. Brigthness is increased/decreased in single steps.
2. The Brigthness indicator is not shown.
Same issue on my Thinkpad X201 (Ubuntu 13.04 64bits). I also noticed that if I click on an entry of the menu bar of any application (for example File menu of Firefox), then use the function buttons to increase/decrease brigthness :
1. Brigthness is increased/decreased in single steps.
2. The Brigthness indicator is not shown.