Switch between layouts?

[emiltin]

There are examples of signs with a bit map display that can work in differenrt modes - e.g either as a warning icon, or as a speed limit sign.
Such cases could be handled by a single image display, but that requires you to render everything yourself, and you loose the ability to interact with e.g. a warning display using named symbols. etc.

We should consider providing the ability to switch between different display layouts. Each layout would contain a different set of display elements (components).