[applegeek]

The cap just popped off during normal use. I have AppleCare, so should I contact Apple or is there a way to fix it? I have tried to put it into place a few times, but no luck.

Thanks

[Waragainstsleep]

Inspect the key underneath to see if it looks broken anywhere. If not keep trying to reattach it, some apple keys can be fiddly to put back on, even to a seasoned pro.
If its broken, call up Applecare and get them to agree to cover it under warranty before taking it for repair.