Make setting initial first responder in IB work

AppKit/CPWindow/CPWindow.j

@@ -257,6 +257,7 @@ var CPWindowSaveImage       = nil,
 
     CPToolbar                   _toolbar;
     CPResponder                 _firstResponder;
+    CPResponder                 _initialFirstResponder;
     id                          _delegate;
 
     CPString                    _title;
@@ -434,6 +435,12 @@ CPTexturedBackgroundWindowMask
     return _CPBorderlessBridgeWindowView;
 }
 
+- (void)awakeFromCib
+{
+    if (_initialFirstResponder)
+        [self makeFirstResponder:_initialFirstResponder];
+}
+
 - (void)_setWindowView:(CPView)aWindowView
 {
     if (_windowView === aWindowView)