public void UngroupShapes(GroupBox el, bool dispose = true)
{
List <GraphicElement> intersections = FindAllIntersections(el).ToList();
// Preserve the original list, including the group boxes, for when we update the screen,
// So that the erased groupbox region is updated on the screen.
List <GraphicElement> originalIntersections = new List <GraphicElement>(intersections);
el.GroupChildren.ForEach(c => c.Parent = null);
el.GroupChildren.Clear();
EraseTopToBottom(intersections.AsEnumerable());
elements.Remove(el);
intersections.Remove(el);
DrawBottomToTop(intersections.AsEnumerable());
UpdateScreen(originalIntersections); // remember, this updates the screen for the now erased groupbox.
if (dispose)
{
el.Dispose();
}
}
