>If I programmatically say ThisCommandButton.Enabled=.T., and if ThisCommandButton is already enabled, does VFP recnogize this and ignore my request to repaint the control, or does it go ahead and repaint the control anyway?

I would say that it will repaint the control.

We've done something in some place where we can the value of a property and this property will decide to enable or not. In this situation, we can check if the property is already enable and not to enable the control again.