When you create a new group, two changes will automatically take place
to the set of objects making up the group. First, certain objects may
be excluded or included despite whether they were selected or not;
this occurs to preserve other relationships between objects. Also,
the members of the group become re-ordered with respect to objects
outside the group such that all objects in the group are immediately
in front of, or behind one another. The objects within the group will
retain their relative ordering so the re-ordering will rarely be
noticed. |