iuri you're a lazy bastard
has_default_p: If set to 1, it means that this filter has a default value, and thus cannot be cleared. If not set, the list builder will automatically provide a link to clear the currently selected value of this filter. You only need to set this if you specify a default value in your page's ad_page_contract, instead of through the 'default_value' property below.
thanks claudio
