title: What is the File's Owner (in Interface builder)?
body: <p>I am new to Cocoa and I don't understand the concept of <code>File's Owner</code> of a .nib file.</p>
  
  <p>Here is the way I would see things :</p>
  
  <ul>
  <li><p>Consider a file <code>myNibFile.nib</code> file that describes how a window looks.</p></li>
  <li><p>Now, I want to connect an actual window to this .nib file. So, I create a class <code>myWindow</code>, which is a subclass of <code>NSWindowController</code>. And, to do this connection, I change the <code>init</code> method like this:</p>
  
  <pre><code>     -(id)init
       {
           [super initWithWindowNibName:@"myNibFile"];
           return self;
       }
  </code></pre></li>
  </ul>
  
  <p>So, I understand that when I create an instance of <code>myWindow</code>, the "system" will go and look at the .nib file and create the adequate object.</p>
  
  <p>So, my question are : </p>
  
  <ul>
  <li><p>why do I have to specify that the <code>File's Owner</code> of my .nib file is <code>myWindow</code> ? Isn't it redundant ? </p></li>
  <li><p>I guess it means I didn't really understood what the <code>File's Owner</code>. What is it ? Why does the .nib file have to belong to something ? Can't it be "somewhere" in my "application" and when it is needed, the "system" goes there and use it ?</p></li>
  </ul>
  
  <p>Thanks for helping me to see more clearly in these new concepts !</p>