See if this helps.

Try breaking the problem down.

For any gui widget you only need to know a few things.
* where it is.
* how big it is.
*** is it the control we have focused.
@@@ extra widget specific data. (e.g Captions, Paint states {Pressed, checked, moving...}, user input space....)

It also has only a few basic functions.
* Init. Run once, befor we see it.
* Paint. The code that draws it to the screen.
* OnMouse. handles mouse stuff
* OnKey. handels keyboard stuff.
* DeInit. Clean up, after were finnished with it.
@@@ for extra marks, add in an update for animation stuff.

Control focus is special because You'll probably want it in a form or screen widget, it what allows you to send the mouse and key data to the active widget. It avoid some of the messynes.

Forms or Screens are just containers (arrays) for widgets.