I seem to have a problem overriding a nib name of a window controller for a window I am creating programmatically. My Xcode keeps suggesting NSNib.Name? as a var type for windowNibName property of MainWindowController and I am not able to convert it to String either. Funny thing is that there is no such problem in my projects created a year ago. There, Xcode suggestions are of the same String type. Could anybody please suggest anything helpful?
MacOS 10.13.3, Xcode 9.2
Error text: “Property ‘windowNibName’ with type ‘String?’ cannot override a property with type ‘NSNib.Name?’”