fix cursor visibility in OSX

src/node.h

@@ -110,6 +110,7 @@ public:
 
     glm::mat4 m_proj;
     glm::mat4 m_mvp;
+    bool m_mouse_focus = false;
     bool m_mouse_inside = false;
     bool m_flood_events = false;
     bool m_force_mouse_capture = false;