The rollup effect on double click is called window shading.
Raising and lowering are used to control windows stacking.
For example put 2 small windows (pcmanfm or ...) on your desktop and put a maximized window in front of it, now choose lower for the maxed window and the other 2 will come above it.
The windows you raise keep above the ones you lowered even when focussing the lowered windows.
e is a geeky window manager, it even does tiling.