Quick fix for graphs not saving, needs more investigation.

MaterialGraphProject/Assets/GraphFramework/SerializableGraph/Editor/Drawing/AbstractGraphDataSource.cs

                 foreach (var drawableNodeData in found)
                     drawableNodeData.MarkDirtyHack();
             }
+
+            EditorUtility.SetDirty(graphAsset.GetScriptableObject());
         }
 
         private void UpdateData()
         public void AddNode(INode node)
         {
             graphAsset.graph.AddNode(node);
+            EditorUtility.SetDirty(graphAsset.GetScriptableObject());
             UpdateData();
         }
 
             graphAsset.graph.ValidateGraph();
+            EditorUtility.SetDirty(graphAsset.GetScriptableObject());
             UpdateData();
         }
 
         public void AddElement(GraphElementData element)
         {
             var edge = element as EdgeData;
-            if (edge.candidate == false)
+            if (edge != null && edge.candidate == false)
+                {
+                    EditorUtility.SetDirty(graphAsset.GetScriptableObject());
+                }
                 UpdateData();
                 return;
             }