title: Design view disappeared from Interface Builder
body: <p>All of a sudden, the visual design window disappeared from my Interface Builder. It is a regular UIView, has some UIImageView, UILabel, and UIButtons on it. When I open IB, I can see the document window (with File's Owner, First Responder and View in it), Library and Inspector, but the visual design window disappeared. Double click on "View" in the  document window doesn't do anything. If I go to List mode, I can see all the components on the view, but just can no longer find the visual design window. All other XIB can open just fine, only this XIB lost its design window. </p>
  
  <p>First I thought maybe it was hidden somewhere on the screen. Tried all kinds of things, even rebooting the computer, but nothing helped.</p>
  
  <p>Can anyone help? Thanks in advance! By the way, I'm running SDK 3.2 Beta 3.</p>