Another newbie question: What is the method for making one scrollable area the parent of another. For example, I have a main view that can be scrolled vertically and a series of "trays" that can be scrolled horizontally. The trays are a component of the main view and can be scrolled with it, in a vertical direction. But only the trays can be scrolled in a horizontal direction. A recent example of what I have in mind is the category page for selecting an Apple watch.
Does anyone know of an example of this behaviour, which they could share.