public bool Visible {get; set;}

{
  // Note: call within QueuedTask.Run()
  {
    //Get the variable profile whose renderer will be changed
    var variable = voxelLayer.SelectedVariableProfile;

    //Check DataType
    if (variable.DataType != VoxelVariableDataType.Discrete)
      return;//must be Discrete to have a UV Renderer...

    var renderer = variable.Renderer as CIMVoxelUniqueValueRenderer;

    //A CIMVoxelUniqueValueRenderer consists of a collection of
    //CIMVoxelColorUniqueValue classes - one per discrete value
    //in the associated variable profile value array

    //Get the first class
    var classes = renderer.Classes.ToList();
    var unique_value_class = classes.First();
    //Set its visibility off
    unique_value_class.Visible = false;

    //Apply the change to the renderer
    renderer.Classes = classes.ToArray();
    //apply the changes
    variable.SetRenderer(renderer);
  }
}