how to let a layout cover the whole screen?

I believe appRect is automatically pushed down 24px IF there are widgets loaded in WIDGETS. If there aren't widgets loaded then it should return the full screen. For instance:

>Bangle.appRect
={ x: 0, y: 24, w: 176, h: 152,
  x2: 175, y2: 175 }
>reset()
...
>Bangle.appRect
={ x: 0, y: 0, w: 176, h: 176,
  x2: 175, y2: 175 }

The issue really is while you can do what you mentioned to force fullscreen, if a widget updates (eg battery, bluetooth, etc) it'll just redraw over the layout. So realistically the only real way to get fullscreen is to have loaded a seperate app that then never calls loadWidgets (since you can't easily unload widgets).

Just a note on the settings screen - it looks great, and I know the current E.showMenu is not nice at all, but I feel like if at all possible it would probably be good to try and improve E.showMenu to make it better rather than getting in the situation where every app implements its own settings screens.