With the new panel widget, it becomes useful to be able control whether widgets are displayed "above" or "below" other panels. In the example below, we selected the square panel with the green fill and sent it to the back so it is now being partially covered by the gray panel.
Note that the gray panel is partially transparent which is why you can still see the green fill albeit with slightly lighter green in the covered area. By making the gray widget be non-transparent, that green area is now completely covered.
Here is an example where we have two LED widgets that have been sent to the back so that they are behind the knob. This means that they can be used as indicators but you can't actually click on them by mistake.
