[cyleigh]

Rob, thank you very much. That should have been obvious!

As a further question, I'm still not sure how to test for the condition in an if statement? I know it isn't a good idea, but I still want to know how to do it. For example, when testing if a shape is part of a group:

if (group of vertex is not missing value) then
  -- stuff
end

or even

set myGroups to (group of myCanvas whose id is (id of group of vertex))

both fail when the shape isn't part of a group.