>Am I correct that the menu item 'Save As Class ...' is only enabled when editing a SCX,
>but is disabled when editing a class?


Correct. To save a class as a class, either:
(1) Select all objects on the class, then paste onto a blank form and save from there (you'll lose all properties and methods), or
(2) Create an instance and execute the this.SaveAsClass() method on the object.