code: public ScreenComponent setupDefaultView(ScreenLoc itsLocation, ComponentParent targetScreen, Convert converter, int iDisplayFieldDesc, Map<String, Object> properties)
      {
          return null;
      }
docs: Set up the default screen control for this field.
  You should override this method depending of the concrete display type.
  @param itsLocation Location of this component on screen (ie., GridBagConstraint).
  @param targetScreen Where to place this component (ie., Parent screen or GridBagLayout).
  @param converter The converter to set the screenfield to.
  @param iDisplayFieldDesc Display the label? (optional).
  @return Return the component or ScreenField that is created for this field.