By defaut, the root viewcontroller of the main window in story board is connected to a single NSViewController object, and I can find the segue defined in the IB panel. However, If I delete the segue and try to bring another ViewController as the root viewcontroller, i can not just drag a segue from the window to the destination viewcontroller, nor can I manully add segue in the IB panel. Is programming the only way to change the window root view controller?
change window root view controller in storyboard
Interface Builder sometimes likes to select the
NSWindow rather than the NSWindowController during operations like this. Try dragging from the Inspector, or ctrl-drag from the blue circle representing the controller at the top of the Storyboard scene.