title: adding an invisible button to the background in IB
body: <p>I'm working with Xcode doing a Ipad app.
  i simply want user to click anywhere on screen (not counting text fields) to perform some IBAction.I'm using an invisible button that covers my whole view.
  Since I have some text fields in my view,i need to add this invisible button to the background of my user interface. I cant seem to find this option in the button attributes? any help?</p>