This group arranges its children vertically or horizontally, aligned within the rectangular bounds,
optionally spaced with lines drawn between the objects, bordered, and with a background.
As with any other group, adding a child to this group does not change its selectability.
You will need to decide whether the user can select individual items in the list of
objects. If an item is selectable, it should have its DragsNode property set to true
and it probably should not be resizable.