Hola Jose Luis

Te adjunto el texto que al respecto aparece en el libro "Hacker's Guide to VFP 6.0" de Tamar Granor y otros.

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AddObject and NewObject (added in VFP 6) are similar, but NewObject doesn't require SET CLASSLIB or SET PROCEDURE first. The difference between these two is quite similar to the difference between CreateObject() and NewObject(). We suspect, as in that case, that we'll find ourselves using NewObject() more and more, once we remember to do so.

NewObject() also offers the opportunity to add objects based on classes built into APP or EXE files, without having to have the library available as a separate VCX or PRG.

At runtime, the object added to the container always has Visible set to .F., even if you explicitly set it in the object's Init. This lets you do all the fiddling around you need with the new object before it becomes visible, so the user doesn't see what's happening. To ensure the display does not update until all changes are made, you can also toggle the form's LockScreen property.

Because these methods work at design time as well as runtime, they're extremely useful in Builders. You can get the user's input, add the appropriate objects and set them up the way the user wants. For more on Builders, see "Builders and Wizards and Bears, Oh My!" on the book's CD.

Don't confuse these methods with the ones used to add items to a list or combo box.

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Saludos