In the Model Specification dialog, what do the "Abstract," "Leaf," and "Root" checkboxes mean?


I could not find anything in the help file or searching on the internet or here in the forum.


Hi Grant,

These are properties inherited from UML’s Classifier. Abstract means it cannot create instances, Leaf means it has no sub classes, while Root means it has no super class.

Hope this helps,



Well, I know what those terms mean for a class. But they don’t really have meaning for a package. Does the UML spec allow for packages to have “visibility” modifiers? If not, then these checkboxes need to be removed from the package specification dialog.


Hi Grant,

According to the UML specification, Package generalizes from PackageableElement, and so it also inherits the visibility attribute.

Best Regards,