Document interaction between height, menuheight, etc. for CDialog #1
Description
The current documentation shows working examples, but it does not act as a tutorial explaining how these examples were arrived at. Consequently, it fails to explain certain facts, such as that setting menuheight in a dialog will have no effect if you don't also set height so that the dialog itself expands to allow the menu to achieve the specified height.
Basically, dialog(1) doesn't auto-size things sensibly, as might be expected from other UI toolkits: Tk, Flex, HTML... You can't expand an inner element's size and expect the outer element to resize to contain it because you haven't given an explicit size. It's all fixed sizing, so that you must manually take into account things like the terminal size and the space given to UI chrome when working out your sizing values.
Once upon a time, auto-sizing was rare. It is what made Tk interesting back in the day. With the web, it's become expected, but dialog(1) hasn't kept up. It thus falls to the documentation surrounding it to explain what might once have needed no explanation.