I wanted to simplify my problem, that's why I put the constraints in the subclass (class Container) It is exactly the same if I put the constraints in the code of the ViewController  I think the problem is that Interface Builder doesn't apply constraints. If I add the following method:  func setupIBConstraints() {     if (superview?.frame.size.width)! < (superview?.frame.size.height)! {       label.text = "setupIBConstraints(.CR \(superview?.frame.size.width)"       label.sizeToFit() self.layer.frame = CGRect(x: 30, y: 100, width: (superview?.frame.size.width ?? 0)-60, height: (superview?.frame.size.height ?? 0)-300)     } else {       label.text = "setupIBConstraints(.CC ou .RC \(superview?.frame.size.width)"       label.sizeToFit()       self.layer.frame = CGRect(x: 20, y: 50, width: (superview?.frame.size.width ?? 0)-100, height: (superview?.frame.size.height ?? 0)-100)     }   } and in method layoutSubviews() I replace setupConstraints(theOrientation) by  #if TARGET_INTERFACE_BUILDER      setupIBConstraints() #else     setupConstraints(theOrientation)  #endif  I can see a correct result in Interface Builder  it proves that code is well executed by Interface Builder change of frame is OK for IB but it doesn't apply constraints  I would reformulate my question: how to apply programmatic constraints in IB  Of course, I can write constraints in IB but I thought it was possible by program and see the results in IB

The point is that if the UIElements of my cell have layout inferred, I can see in IB all the elements placed correctly. But when the program is running, none of the constrains applied. In the other case, if the UIElements have layout autoresizing make, if I change from portrait to landscape the elements are not placed correctly

Yes of course I set variations of constraints But I don't see the result in Interface Builder. Imagine just a UItableViewCell. If I made variations, in portrait mode the width will be for instance 400, and in Landscape Mode the width will be 800. But there is no visual in IB. If I go in portrait mode, or in landscape mode, the visual doesn't change, even if I put the width in constraint

I'm very ashamed It effectively was an internal error. The code was never called Please excuse me, all of you, for disturbing

I confirm the variable aController is not nil so displayAlert is called

All is my faultThe lesson of it is we have to think much more harder before making a postMy subclassed control, in the override function becomeFirstResponder didn't called super.becomeFirstResponder (the function of the NSTextField). As a result, currentEditor() of the control returned nil.When calling super.becomeFirstResponder, the function currentEditor returns the desired editor.Sorry about all this

when the instructionvar fieldEditor = ctrlRch.currentEditor()is executed, fieldEditor is nil

ctrlRch.setSelectedRange = NSMakeRange(ctrlRch!.stringValue.count-1, 1)gives:Value of type 'NSTextField' has no member 'setSelectedRange'

after the preceding answer, I saw that you added questionsAre you sure it is the textField (ctrlRch) ?After the window?.makefirstRespnder(ctrlRch), if i write Swift.print("firstResponder is \(window?.firstResponder)") I have the following in the debugging console: firstResponder is Optional(&lt;ivrit2.cTextField: 0x1020172f0&gt;)If I understand well, fieldEditor is a NSText. Could you check the type ?No, I can't check the type of fieldEditor, because the currentEditor() function of ctrlRch always return nilYou use selectedRange on NSText. Why not set selectedRange on the textField ?If I write ctrlRch.selectedRange I hve the following error: Value of type 'NSTextField' has no member 'selectedRange'

1. What is the original myKeyDown that you override ?The NSWindowConroller is a subclass of a baseClass, but the super.myKeyDow is never called. So the override keyword has no importanceThe myKeyDow is called by the following mechanism:_eventMonitor = NSEvent.addLocalMonitorForEvents(matching: .keyDown) { if self.myKeyDown(with: $0) { return nil } else { return $0 } }2 What is ctrlRch ? a textField I guess? What is the currentDitor doing ?ctrlRch is a subclass of NSTextField and I just want it to get the focus when the user tap a key on his keyboard.the current editor, as referred to the apple dcumentation returns the field editor for the currentControl or nil if the receiver does not have a field editor.In my case, I always get nil for fieldEditor invar fieldEditor = ctrlRch.currentEditor()3. Where do you set focus to the textField ?I'm not sure but I think that the following code put the focus on ctrlRch:window?.makeFirstResponder(ctrlRch)In fact, if in my subclassed ctrlRchI write the function becomeFirstResponder and resigneFirstResponder, I can see that when I call makeFirstResponder in my controller, becomeFirstResponder is called and immediatly resigneFirstResponder is called4. Do you get a print logged when you type a char ?I'm not sure waht you mean, but if I writeSwift.print(event.description)I have a log of each key pressed

Ho yes, sorry my mistakeSo thank you Quinn

Thank you ClaudeIn fact what was missing was the encode function, as my Class is derived not from Codable but from another class

I think you are rightThe declaration of the fetch function as simply to be:func fetch(_ tableview: NSTableView, _ row: Int, params: Parameters, response: ResponseListModel&lt;T&gt;.Type, completion: @escaping (Bool) -&gt; Void) {}in this case, the compiler acceptsself.moderators.insert(contentsOf: rep.moderators, at: 0)

No of course it isn't the real codeI wanted to isolate the response of the compilerThe Code is quite complexclass ResponseListModel: Decodable { var moderators: [T] var totalEnreg: Int var hasMore: Bool var currentPage: Int var indexPage: Int = 0 var limit: Int = 0 var nbPagesInMemory: Int! var fetchingData: Bool = true enum CodingKeys: String, CodingKey { case moderators = "items" case hasMore = "has_more" case totalEnreg = "total" case currentPage = "page" } func destroyPageData(_ index: Int) { moderators.removeSubrange(index..&lt;index+min(limit, moderators.count))&lt;br=""&gt; } func rowLoaded (_ row: Int) -&gt; Bool { let firstIndex = (currentPage-1)*limit let lastIndex = firstIndex + moderators.count return row &gt;= firstIndex &amp;&amp; row &lt; lastIndex } func rowIndex (_ row: Int) -&gt; Int { return row - (currentPage - 1)*limit } func row(_ row: Int) -&gt; T { let rowCalculee = row - (currentPage-1)*limit return moderators[rowCalculee] } func clean() { moderators.removeAll() } func fetch(_ tableview: NSTableView, _ row: Int, params: Parameters, response: ResponseListModel.Type, completion: @escaping (Bool) -&gt; Void) where T: Decodable { Swift.print("ca tourne pour row=\(row)") if !fetchingData /*|| !rowLoaded(row)*/ { fetchingData = true // 1 calculate what part of the array has to be destroyed if row &lt; indexPage { destroyPageData((nbPagesInMemory-1)*limit) } else { destroyPageData(0) self.indexPage += limit } // 2 Fetch data if necessary StackExchangeClient().fetch(request: BaseRequest(parameters: params), dataResponse: response, completion: { result in switch result{ case .failure(_): completion(false) case .success(let response): let rep = response as! ResponseListModel self.currentPage += rep.moderators.count / self.limit if row &lt; self.indexPage { self.moderators.insert(rep.moderators, at: 0) } else { self.moderators.insert(contentsOf: rep.moderators, at: self.moderators.count) } self.moderators.append(rep.moderators) let rows = NSIndexSet(indexesIn: NSMakeRange(row, self.indexPage+self.moderators.count-1)) as IndexSet let cols = NSIndexSet( indexesIn: NSMakeRange(0, tableview.numberOfColumns)) as IndexSet DispatchQueue.main.async { self.fetchingData = false tableview.reloadData(forRowIndexes: rows, columnIndexes: cols) } completion(true) } }) } }I can't correctly reproduce the header of the fetch function with the advance.button of this forum, it corrects the codemy code isfunc fetch&lt;T&gt;(_ tableview: NSTableView, _ row: Int, params: Parameters, response: ResponseListModel&lt;T&gt;.Type, completion: @escaping (Bool) -&gt; Void) where T: Decodable {}and my problem appears on lines 63 and 65

You are right, I chosse the firstbecause one thing I didn't told is that my application is document based so I can have multiple splitview and multiple toolbars.That"s why I was looking for the ancestorThank's