ScreenSandbox

From SMTheming Wiki

ScreenSandbox is best described by the comment it contains:

/*
 * Area for testing.  Throw whatever you're working on in here.  If you
 * don't want stuff in here to be wiped out by the next guy who works on something,
 * make a separate screen and add a hook into ScreenTest; this one's just a
 * scratchpad.
 */

It derives from Screen and is very bare bones, not even containing any children or metrics. It's a good place to start if you're working on making your own custom screen class in the source code, but it can also be used as a theming scratchpad as well.