Another big advantage of the technique above that I forgot to mention is when the functional global outputs data. For instance, let's assume the Execute case of the functional global outputs the current value of the ComboBox. That means the functional global has a string output. But this string output won't make any sense if referenced from the Read case, since it only involves initialization.
The technique above allows you to only output data from a functional global only where it applies by ignoring it in the polymorphic instances where it doesn't apply.
Jarrod S.
National Instruments
