Translation between IMGUI property drawer and custom UITK hierarchy provided in the repro project is not trivial. The Context Menu not showing up is a result of the user's DropdownPropertyField not being recognized by the binding system and thus not generating a Context Menu for its label. There is currently no easy way in UITK to make the label of a user-defined VisualElement inherit from the Context Menu of a parent PropertyField. You can however instantiate a PropertyField in the CreatePropertyGUI method, modify its inner content to reflect you needs, and keep its label as is to get the Context Menu you want.