DECLARE
   TabEvent  VARCHAR2(80);
   TabNumber NUMBER;
BEGIN
   TabEvent := :system.custom_item_event;
   IF (UPPER(TabEvent) = CLICK) then
      TabNumber := VBX.Get_Property(PRIORITY_TAB, CurrTab);
      IF TabNumber = 0 then
         show_view(ALL_EMPLOYEES);
      ELSIF TabNumber = 1 then
         show_view(CONTACT);
      END IF;
   END IF;
END;