create NodeDialogOpen and bind it to the layout template

engine/canvas.h

@@ -39,6 +39,7 @@ class Canvas
     BrushMesh m_mesh;
     bool m_dirty = false;
 public:
+    static Canvas* I;
     bool m_erase = false;
     glm::mat4 m_mv;
     glm::mat4 m_proj;
@@ -70,6 +71,7 @@ public:
 
     std::vector<Layer::Snapshot> m_layers_snapshot;
 
+    Canvas() { I = this; }
     bool create(int width, int height);
     void resize(int width, int height);
     void layer_add(std::string name);