diff --git a/horizontal_layout_node.h b/horizontal_layout_node.h
index d1643cf44..eeafa600c 100644
--- a/horizontal_layout_node.h
+++ b/horizontal_layout_node.h
@@ -17,7 +17,7 @@ public:
   }
 
   int numberOfChildren() const override { return m_numberOfChildren; }
-  void incrementNumberOfChildren() { m_numberOfChildren++; }
+  void incrementNumberOfChildren() override { m_numberOfChildren++; }
 
   void moveCursorLeft(LayoutCursor * cursor, bool * shouldRecomputeLayout) override {
     if (this == cursor->layoutReference().node()) {
@@ -85,11 +85,6 @@ public:
     addChild(l2);
     addChild(l1);
   }
-
-  virtual void addChild(LayoutRef l) override {
-    LayoutReference<HorizontalLayoutNode>::addChild(l);
-    node()->incrementNumberOfChildren();
-  }
 };
 
 #endif
diff --git a/layout_reference.h b/layout_reference.h
index 29c5d7f2d..31760fcfb 100644
--- a/layout_reference.h
+++ b/layout_reference.h
@@ -20,10 +20,6 @@ public:
 
   LayoutCursor cursor() const;
 
-  virtual void addChild(LayoutReference<LayoutNode> l) {
-    TreeReference<T>::addChild(l);
-  }
-
   LayoutReference<LayoutNode> childAtIndex(int i) {
     TreeReference<T> treeRefChild = TreeReference<T>::treeChildAtIndex(i);
     return LayoutReference<LayoutNode>(treeRefChild.node());
diff --git a/tree_node.h b/tree_node.h
index dbd06fed5..5cddb5fa4 100644
--- a/tree_node.h
+++ b/tree_node.h
@@ -38,6 +38,7 @@ public:
   TreeNode * parentTree() const;
   TreeNode * editableRootTree();
   virtual int numberOfChildren() const = 0;
+  virtual void incrementNumberOfChildren() {} //TODO Put an assert false
   int numberOfDescendants(bool includeSelf) const;
   TreeNode * childTreeAtIndex(int i) const;
   int indexOfChildByIdentifier(int childID) const;
diff --git a/tree_reference.h b/tree_reference.h
index cc5ae1571..cbe4631d4 100644
--- a/tree_reference.h
+++ b/tree_reference.h
@@ -81,6 +81,7 @@ public:
   void addChild(TreeReference<TreeNode> t) {
     t.node()->retain();
     TreePool::sharedPool()->move(t.node(), node()->next());
+    node()->incrementNumberOfChildren();
   }
 
   void removeChild(TreeReference<TreeNode> t) {