I can verify a similar problem on a Dell Inspiron e1505:
Using the Fn Brightness controls (Fn Arrow Up/Down) causes X not to register keystrokes in programs, and ceases OSD of volume/brightness events (OSD for battery WiFi et al never worked - not sure it's supposed to?). Also submenus and right-clicks cease to work.
Toggling to Terminal and back to GUI (Ctrl-Alt F1/F7) restores keyboard/clicking functionality.
I can verify a similar problem on a Dell Inspiron e1505:
Using the Fn Brightness controls (Fn Arrow Up/Down) causes X not to register keystrokes in programs, and ceases OSD of volume/brightness events (OSD for battery WiFi et al never worked - not sure it's supposed to?). Also submenus and right-clicks cease to work.
Toggling to Terminal and back to GUI (Ctrl-Alt F1/F7) restores keyboard/clicking functionality.