---- dataentry configoptions ----
type             : constant
name             : EMPTY_VALUE_PREFIX
purpose          : Set a dropdown prefix which indicates no value
allowed          : A short string
default          : --
status_s         : 
category         : segmentation
----


Using this, you can organise your attribute values to have some useful "empty" values.

For example for your subscribers to set their country, you can put 

<code>-- Select your country</code>

as the first country, which then returns an empty value when chosen. If you then make **country** required, choosing this value will return an error on the subscribe page.