Custom Figure Implementation Follow

I have no idea about the diagram-stuff you are trying to do, but in situations like the ones you describe, what I usually do is I search for instances of the nodes I need within the Project Scope and then copy/paste an instance into my root.

So, in your case, I searched for "FigureParameterAttribute" by means of Ctrl/Cmd+N (2x). ThereI opened the find-usages dialog (Ctrl/Cmd+Alt+Shift+F7) and searched like so:

I found a usage in MovableContentView, and upon pasting it into my file, MPS asks me to import the following:

Notice that you seem to can toggle the FigureParameterAttribute only by means of a intention:

This intention only applies for public static fields and if the extended classifiers contain ViewPropertySpec, apparently:

error intention : false 
available in child nodes : true 
child filter : <all child nodes> 
 
description(node, editorContext)->string { 
 return node.@figureParameterPropertySpecification == null ? "Add figure parameter attribute" : "Remove figure parameter attribute"; 
 
} 
 
isApplicable(editorContext, node)->boolean { 
 if (!node.visibility.isInstanceOf(PublicVisibility)) { return false; } 
 node<ClassifierType> classifierType = node.type as ClassifierType; 
 if (classifierType == null && classifierType.classifier == null) { return false; } 
 
 set<node<Classifier>> allExtendedClassifiers = classifierType.classifier.getAllExtendedClassifiers(); 
 return allExtendedClassifiers.contains(node/ViewPropertySpec/); 
}
 
execute(node, editorContext)->void { 
 if (node.@figureParameterPropertySpecification != null) { 
 node.@figureParameterPropertySpecification = null; 
 } else { 
 node.@figureParameterPropertySpecification = new node<FigureParameterAttributeViewProperty>(); 
 } 
}