Document how to create new components
I have written some simple examples in Nimx, but it is not clear to me what kind of pattern to follow to create custom components. By this I mean:

* either a customization of an existing component (say, buttons with a different style)
* or some kind of new component that possibly does its own layout but includes other components (for instance a box containing multiple buttons, only one of which can be active at a moment of time)

A component could possibly hold some state about its current appearance.

Are there some examples or possibly some guidelines for custom components?