Sets or returns the name of the callback function for this menu
item as a String. The callback
function is called when the item is selected and is executed as a
single undo event by Softimage. You can always undo/redo the action
of a menu item callback function provided the function calls
undoable commands and/or object model methods.
The callback function must be implemented in the plug-in's file as
described in Definition
Callbacks for Menus. If your menu is attached to a contextual
menu, the currently selected objects are passed in to your
callback. The target object under the cursor is also passed in as
part of the selected objects. However, if no objects are selected,
then only the target is passed in. The objects can be retrieved
through the Context.GetAttribute method with
"Target" specified as the value for the AttributeName
parameter.
The menu item that points to a callback has the following caption:
item_name [origin]
...where 'item_name' = the name of the menu item and 'origin' = the
origin of the callback ([u] for user, [w] for workgroup).