Moving controls interactively

Hello,
I'd like to let an user move controls around the window, i.e. he  
should be able to both rearrange buttons, text fields, labels and  
images and to use them.

I'm using a non NSDocument based project in XCode, I created a  
MyWindow subclass of NSWindow and I overrode sendEvent.
In sendEvent I check if a flag in controller is set and then either  
pass along sendEvent by running [super sendEvent:event]; or I set the  
control position using setFrame.

Is this way correct?
Can anyone point me to an example of such a code, if there's one?


Regards

--
Andrea