inputField.ActivateInputField() not working

Hello,

I am trying to focus an InputField. At another place in my game I got the following to work (the InputController is attached to the InputField GameObject, which is active):

 public class InputController : MonoBehaviour
 {
         private InputField inputField;
         
         public void Setup()
         {
                     inputField = gameObject.GetComponent<InputField>();
                     inputField.ActivateInputField ();
                     inputField.Select ();
                     Debug.Log("activated input field: " + inputField.isFocused);
         }
 }

But in this case the InputField does not get activated (as the caret is not showing) and inputField.isFocused is logged with false. Anybody got an idea why the InputField does not get focused? Any help is appreciated.

EDIT: I've looked a little more into what is happening:

• If I call inputField.isFocused inside of Update, it remains false even some frames after Setup() has been called.

• The inputField is set to interactable.

• The placeholder is showing at the correct position inside the input field, so is the actual user input. If I click the inputField, the caret is showing at the correct position, too.

• When looking at the input field in the editor, it has a child named InputField(Clone) Input Caret. This has the same position as the placeholder (which is shown correctly), but is not showing. If I click into the inputField, the caret is showing, but the GameObject of the caret does not change at all.

• UnityVersion used: 2017.3.1f1 Personal

  ---

EDIT: The code that calls Setup() is as follows:

 private GameObject AddInputGameObject()
 {
     GameObject inputField = Instantiate (inputFieldPrefab, panel.transform);
 
     Text placeholder = inputField.transform.Find("Placeholder").GetComponent<Text>();
     placeholder.text = "Please enter sth";
     
     InputController inputController = inputField.GetComponent<InputController>();
     inputController.Setup();
     
     return inputField;           
 }