From what I understand and what I can see in your code, you want to modify a widget when the UI is open. However you never trigger the rebuilding of the window. For example, see the Spec docs that I sent, where in 9.1 there is code that calls buildWithSpecLayout: . 

Actually, I am not sure you need to subclass DynamicComposableModel since the number of widgets never changes. You can use a normal ComposableModel subclass and use what is detailed in 9.1 to change the layout between the two options you want to have (a TextModel or a GlamourPresentationModel).