Xcode component installation hangs

One day, I wanted to do something with Xcode, so I opened it, and it wanted to install the Mobile Device Connectivity Framework. I don't actually have a mobile device, and I never do any iOS programming, but it requres this somehow. I select Install, but nothing happens other than a barber pole status bar under "Installing Files." Ever. No activity whatsoever. I did not attach gdb to Xcode to try to find out hat was going on, although you probably didin't need to know that. What is going on, why is it going on, and how can I make it not go on?