The surface lookup field in the marketing form represented in the portal functionality is different form the CRM lookup field functionality. In the lookup filed on the portal the customer needs to type something in the lookup field and then the drop down menu is activated when the lookup field in the CRM is activated only when you click on the field. My suggestion is in order the Lookup filed functionality in the portal is more customer friendly --> is when the customer click on the lookup field the dropdown menu to be activated /as it is working in the CRM/ . I have couple customer which complain regarding this functionality. Thank you in advance!