Initial value of select is lost if no selection is made

Context: I'm using jquery ajaxForm to submit a form.  Browser is Chrome on OSX.
I'm setting an initial value of the combobox by setting the attribute selected="selected"
on one of the option nodes.

What I see:
When the form is drawn, the combo box shows the correct preset value.  However
if I submit the form without touching the combo box, it sends an empty value
to the server.  If I click on the combo box and make a selection, it passes a correct
value to the server.

What I expected:
I expected that if the combo box was not touched, the initial value will be passed back, as
it would be with a standard select element.

Observations:
I see that the hidden element that is created is not initialized with the initial value
of the select.  I've attached a commit that copies the initial 
value of the select element to the hidden element.  This solves the problem for me.