An LSubOverlapView is the SuperView of the LButton objects below. An LSubOverlapView does not draw. It just sets up the clipping region to handle subpanes which may overlap.
The Buttons darken when the mouse is down inside them. Notice that as as you hold the mouse button down, the Button lightens if the mouse moves outside the Button or into another Button which overlaps it.
See the FocusDraw() function of LSubOverlapView for details.
