fix: predams: ExpressionChangedAfterItHasBeenCheckedError when clicking on a...

fix: predams: ExpressionChangedAfterItHasBeenCheckedError when clicking on a wall then on a basin on the graph

refs #522

src/app/components/basin-fieldset-container/basin-fieldset-container.component.ts

@@ -22,10 +22,11 @@ export class BasinFieldsetContainerComponent extends FieldsetContainerComponent
 
     protected onFieldsetListChange() {
         // disable "add" button (and "how many children" select)
-        this._fieldsetComponents.forEach(fs => {
-            fs.showAddChildren = false;
-            fs.showMoveArrows = false;
-        });
+        setTimeout(() => // setTimeout to avoid ExpressionChangedAfterItHasBeenCheckedError
+            this._fieldsetComponents.forEach(fs => {
+                fs.showAddChildren = false;
+                fs.showMoveArrows = false;
+            }));
     }
 
     protected addSubNub(after: FieldSet, clone?: boolean): void {