PropertiesQuestion does not provide the means to:

1.
 - Make the value for particular property visible AND read-only (grayed).
 - Make sure that the choice will not be shown for such properties.
   In general, the choice is always shown, not depending on the fact if custom values allowed or not
   (and the list always includes the value of the property).

2. Hide the row on the properties table. API is available (e.g., ValueConstraints constructor parameters,
    but is not implemented (these values are ignored).

Unfortunately, an approach with custom renderers/editors for prop cells does not work for us,
because it leads to huge code duplication.