If you have upgraded to Lion and you also use the IdeaVIM plugin you may be annoyed by Apple turning of key repeating (hold down a key and it repeats). Wierd! Anyway, this is a problem if you use h,j,k,l for navigation with IdeaVIM and want to move by holding down those keys.
You cannot turn off this odd decision via System Preferences, however, there is a defaults write you can use, from Terminal:
defaults write -g ApplePressAndHoldEnabled -bool false
It looks like you have to reboot before it takes effect. Although you may want to try just restarting IntelliJ and see if that works before going for the reboot (I just went for a reboot and all is well now).