Ok now that I have actually read your post I see what's going on... if your using an apple keyboard which i assume you are you can see that the F_ keys have little pictures on them, such as the F4 key which has a picture of the Dashboard logo on it and so thats what it is set to do, if you want them to do what they say in keyboard shortcuts and not what's painted on them go to system preferences>keyboard and mouse>keyboard and check off the box that says "Use all F1 F2 etc. keys as standard function keys"