Question How can i force a re-layout after manually adding elements to a dialog?

I have a dialog which has a fixed upper part containing text and a dynamic lower part with options that the player can take. These options differ every time so I create the buttons manually creating them and adding them to a container element like this:

Code (CSharp):

1.            
2. // get a reference to the container            
3.            _optionsContainer = _storyDialog.Q<VisualElement>("options");
4. // clear it
5.             _optionsContainer.Clear();
6. // add buttons for each option
7.             foreach (var option in command.Descriptor.options)
8.             {
9.                 var button = new Button(() => { ChooseStoryOption(option); });
10.                 _optionsContainer.Add(button);
11.             }
12. // show the dialog.
13.             _storyDialog.visible = true;
14.  

However when the dialog shows the layout is really quite broken:


Only after i manually drag the viewport size in the Unity-editor the dialog properly re-layouts and looks the way it should:



I am not sure if this is a bug or if I am just not using the system correctly. How can I force a proper re-layout of the whole dialog after I modified the UIElement structure?

 

I see, thank you. Good to know that I used the system correctly