This seems to be a bug in the later versions of Xcode – specifically 4.0 and later, though it seems to work in some cases without any problems. When you select a UI control in the storyboard, open the AssistantEditor and control-drag it to the relevant file in the editor, nothing happens.
A lot of people face this problem and the general solutions provided are:
- The wrong file is open in the Assistant Editor
- The correct class file needs to be assigned to the the Storyboard, specially if you are using a custom Viewcontroller class.
- Deleting the working files of the project and loading it again in Xcode.
I was not able to resolve my problem with the above solutions. But the reason for the problem was clear – the correct class was not assigned to the Storyboard so it was rejecting the creation of an Outlet. I found that out of 5 scenes in the storyboard, only the last 2 were having this problem and the other 3 did not have this problem. On investigating this further, I found that the the storyboard had not assigned the customClass and customModule attributes to the viewController xml tag to the two scenes where this problem existed, whereas the other 3 scenes where Outlets could be created, these attributes were there.
After manually adding the attributes directly in the Storyboard file xml, the problem went away and the Outlets could be created.
<viewController id="BYZ-38-t0r" customClass="ViewController" customModule="Swerk" customModuleProvider="target" sceneMemberID="viewController">