Prevent PAB from offering irs children' linkable values

src/nub.ts

 import { CalculatorType, ComputeNode } from "./compute-node"; // nghyd build fails when commenting CalculatorType @WTF
 import { Dichotomie } from "./dichotomie";
-import { acSection, IParamDefinitionIterator, ParamDefinition, ParamsEquation, ParamsEquationArrayIterator,
-         Session, Structure } from "./index";
+import { acSection, IParamDefinitionIterator, Pab, ParamDefinition, ParamsEquation,
+         ParamsEquationArrayIterator, Session, Structure } from "./index";
 import { LinkedValue } from "./linked-value";
 import { ParamCalculability } from "./param/param-definition";
 import { ParamValueMode } from "./param/param-value-mode";
@@ -500,9 +500,11 @@ export abstract class Nub extends ComputeNode implements IObservable {
             }
         }
 
-        // 3. children Nubs
-        for (const cn of this.getChildren()) {
-            res = res.concat(cn.getLinkableValues(src));
+        // 3. children Nubs, except for PAB
+        if (! (this instanceof Pab)) {
+            for (const cn of this.getChildren()) {
+                res = res.concat(cn.getLinkableValues(src));
+            }
         }
 
         return res;