PortParameters cannot be drag-instantiated from Outline/Items of Interest trees
You cannot drag out a PortParameter from the Outline/Items of Interest trees. The reason is ptolemy change r57732 to ParameterPort to avoid bug#4915:
Parameter notDraggable = new Parameter(this, "_notDraggable");
This change should be removed and bug#4915 properly fixed. As part of this, we need to ensure proper behavior when dragged out from the Outline tab, and the Items of Interest panes in both Reporting and Plotting.