LP1830923 Combobox LP1844812 regression fix

LP1830923 Combobox LP1844812 regression fix

Allow a combobox to start with an empty array that is later filled by
the caller.  This was broken due to changes which prevented the combobox
from seeing an empty/stub array as being different from its
initialization array, thus ignoring empty array as a duplicate.

Signed-off-by: Bill Erickson <berickxx@gmail.com>
Signed-off-by: Remington Steed <rjs7@calvin.edu>
Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>