Options for selection status in relation to previously selected objects.
|ADD_TO||Adds the object to the existing selection; if no object was previously selected, makes the object the only selected object.|
|REMOVE_FROM||Deselects the object.|
|REPLACE_WITH||Selects the object and deselects any previously selected objects.|
|SET_KEY||Sets the key object. At least 2 objects must be selected, and the key object specified must be one of them.|