Gerber OMEGA CP Reference Manual page 266

252 Chapter 24:
Five Steps to Successful Output
Combined objects fade continuously. For example, a radial fill assigned to three objects will
look different if the three objects are combined or if they are uncombined.
Combines and layers
Objects must be on the same layer to combine. If you combine objects that reside on different
layers the objects are automatically moved to the layer of the last selected item.
When moving combined objects to a different layer you must select all objects involved to retain
the Smart Edit attributes. Moving only one object of a combine to a different layer breaks the
Smart Edit link. A warning displays and you are given the option to cancel the move.