The inset prop controls how label_spacing and panel_spacing are applied. When set to auto (default), there is inset spacing around labels and no inset spacing around panels, which means panels are flush with the edges of the parent container. When set to on, spacing is applied around the labels as well as the panels. This works well in a container which has no inner padding of its own. When set to off, all inset spacing is turned off. label_spacing applies between labels rather than around them, and panel_spacing only applies above the panel, making the panel flush with the edges of the parent container.
Inset: auto
Inset: on
Inset: off