The Dynamic Outsides will allow an opening dragged to the edge of the mat to readjust the outside size by adding the Borders around the current openings on the design.
Dynamic OutsidesToggle appears bright when toggled on.
The Border is the area of precisely definable width between the outside edge of a Mat and the edge of the Opening(s) in the Design Editor, Nesting, and Visualization.
When Dynamic Outsides is Toggled On, dragging a new opening to the edge of the mat will adjust the outside size by adding the Border Size around the Bounding Rectangle of the existing openings.
When Dynamic Outsides is Toggled Off, dragging a new opening to the edge of the mat will not readjust the outside dimensions; the outside dimension will remain a fixed size.