I noticed that when i select autocomplete in location input in theme settings if i publish a listing when i input the region or city i get this error "Please enter non more than 0 characters" as you can see in the attachment.
Solution is in oc-includes/osclass/frm/Item.form.class.php the functions
region_text
and
city_text
you need to change from this
parent::generic_input_text( 'region', isset($item['s_region']) ? $item['s_region'] : null, false);
to this
parent::generic_input_text( 'region', isset($item['s_region']) ? $item['s_region'] : null, null, false);
adding the second null will fix the problem
also in city_text need to be modified