I have a IKImageView in Interface Builder and have set the background color to red but it doesn't work when the app is run, it just stays gray.
- I created a brand new Cocoa (OS X) project in Xcode 4.5 with the Cocoa Application template.
 - Added the Quartz framework
 - Dragged an IKIMageView from the Object library onto my window.
 - Change the color to red.
 

                        
I set background color by this:
where
_imageViewis set asIBOutlet IKImageView * _imageView;