We have a donation form that has an optional dropdown field that allows our donors to specify an area to designate their gift to. When no value is selected, I would expect the contact property to be zeroed out. Instead, the contact property remains whatever it was previously set to. So if someone submitted the form with a designation of “Food and Shelter” and at a later date submitted the form with no designation, the designation contact property would still be “Food and Shelter”, rather than null.
This behavior only seems to happen with radio button and dropdown fields. Other types of optional fields are properly zeroed out when no value is specified. This seems like a bug to me, but maybe this is the expected behavior? If so, is there any way to force those fields to update to a null value with jQuery?