Does VisualElmenet.tooltip work at runtime?

I made a minimal example for testing at runtime. The button does change visually when clicked so the mouse is detected but no tooltip pops up. Am I missing some code? Any suggestions?

Code (CSharp):

1. void Start() {
2.         var uiDoc= GetComponent<UIDocument>();
3.         var rootVE = uiDoc.rootVisualElement;
4.        
5.         var ve2 = new Button();
6.        
7.         ve2.style.width = 200;
8.         ve2.style.height = 200;
9.         ve2.style.backgroundColor = Color.black;
10.  
11.         ve2.tooltip = "A toolTip";
12.        
13.         rootVE.Add(ve2);  
14.     }

 

Thank for the answer & link.