The F1 key doesn’t seem to invoke Help properly in KDE4 on my macbook which runs Mandriva. Solved this by

  • Used xev to figure out that the F1 key is attached to the 101 keycode.
  • Created a .xmodmaprc file with the lines 
                   keycode 101 = F1
  • invoked xmodmap ${HOME}/.xmodmaprc in my .bashrc file.

Restarted X and it worked!