title: Interface Builder won't let me double click on any objects in my .xib
body: <p>Ok, I'm fairly new to Xcode, and I've created a few sample projects and added an Object from the Library into the document window, but when I double click on it to open the Inspector it beeps and won't open it. This used to work just fine, double clicking objects to open the inspector, now all of a sudden it doesn't work anymore. I restarted the computer but it's still doing it. Is there something I could have done which stopped this default behavior from working ?</p>