Creates a group for a tkp::canvas window. This code requires some extra work in order to deal with tkp::surface, too. A surface does not support any groups. Does not look feasible at all...
Example 3.65. ::vgcode::dump-configure-PathCanvas using pathgroup
...
debug stdout "pathcanvas passed"
} elseif { {group} == $type } {
append _graphics \
[dumper::pathgroup $ta_name $id \
[dumper::itemproperties $optsl $id {} $target]]