Add quick add block button to Menu Command block select

Closes #211

Assets/Fungus/Scripts/Editor/FlowchartWindow.cs

@@ -1534,6 +1534,15 @@ namespace Fungus.EditorUtils
             return newBlock;
         }
 
+        public Block CreateBlockSuppressSelect(Flowchart flowchart, Vector2 position)
+        {
+            Block newBlock = flowchart.CreateBlock(position);
+            UpdateBlockCollection();
+            Undo.RegisterCreatedObjectUndo(newBlock, "New Block");
+
+            return newBlock;
+        }
+
         protected virtual void DrawConnections(Block block)
         {
             if (block == null)

Assets/Fungus/Scripts/Editor/MenuEditor.cs

@@ -44,10 +44,24 @@ namespace Fungus.EditorUtils
 
             EditorGUILayout.PropertyField(descriptionProp);
 
+            EditorGUILayout.BeginHorizontal();
             BlockEditor.BlockField(targetBlockProp,
                                    new GUIContent("Target Block", "Block to call when option is selected"), 
                                    new GUIContent("<None>"), 
                                    flowchart);
+            const int popupWidth = 17;
+            if(targetBlockProp.objectReferenceValue == null && GUILayout.Button("+",GUILayout.MaxWidth(popupWidth)))
+            {
+                var fw = EditorWindow.GetWindow<FlowchartWindow>();
+                var t = (Menu)target;
+                var activeFlowchart = t.GetFlowchart();
+                var newBlock = fw.CreateBlockSuppressSelect(activeFlowchart, t.ParentBlock._NodeRect.position - Vector2.down * 60);
+                targetBlockProp.objectReferenceValue = newBlock;
+                activeFlowchart.SelectedBlock = t.ParentBlock;
+            }
+            EditorGUILayout.EndHorizontal();
+
+
 
             EditorGUILayout.PropertyField(hideIfVisitedProp);
             EditorGUILayout.PropertyField(interactableProp);