There does not appear to be a clear way to set the
displayed attribute of the ITEM class in a reliable or
interoperable way. The original idea was that it would indicated
if something had been displayed in a source system, enabling a
receiver system to display things in the same way. However, there
is no way the displayed/undisplayed status of data can be written
into the data itself. Further, the current Entry model includes
protocol as a distinct attribute, and most of not all information
which does not by default need to be displayed is found in here.