I’m a total troublemaker. For my first Core Data app I decided to do something nontrivial (multiple windows referring to a single document). Of course nontrivial means that the Interface Builder can only help me so far. So now I’m stuck trying to get things to work out right. Luckily Patrick Geiller has put together a good explanation of how you can share multiple nibs across an application. Now all I have to do is apply this same data sharing technique to the NSDocument instead.
When using multiple NIBs, we need a common object that will share data among them. That object will hold bindings, outlets, target/action shared across NIBs.