I've just started using the Android Studio version of IntelliJ and am following a simple tutorial to create my first app. I'm at the design stage for designing the user interface for the app. It shows a graphic of the smartphone and the "Pallette" section that shows all the possible UI objects. Normally I would be able to drag-n-drop any of those objects over onto the layout form. But when I do that, nothing happens. The UI object (e.g. a Button) does NOT end up in the layout and it also does not end up in the Component Tree.
How do I get drag-n-drop to work for the layout design?