Disabled PlayFromHere in toolbar if irrelevant / Flash Green Link Lock in lecked scene view's toolbar

Editor/PlayFromHere.cs

             EditorApplication.playModeStateChanged += OnEnterPlayMode;
         }
 
+        public static bool IsReady
+        {
+            get
+            {
+                return OnPlayFromHere != null &&  OnPlayFromHere.GetInvocationList().Length > 0;
+            }
+        }
         
         public static void Play()
         {

Editor/SceneViewToolbar.cs

             {
                 using (new GUILayout.HorizontalScope(EditorStyles.toolbar))
                 {
-                    bool play = GUILayout.Toggle(EditorApplication.isPlaying, Contents.playFromHere, EditorStyles.toolbarButton);
-
-                    if(GUI.changed)
+                    if(PlayFromHere.IsReady)
-                        if (play)
-                            PlayFromHere.Play();
-                        else
-                            EditorApplication.isPlaying = false;
+                        bool play = GUILayout.Toggle(EditorApplication.isPlaying, Contents.playFromHere, EditorStyles.toolbarButton);
+
+                        if(GUI.changed)
+                        {
+                            if (play)
+                                PlayFromHere.Play();
+                            else
+                                EditorApplication.isPlaying = false;
+                        }
+
+                        GUILayout.Space(24);
-                    GUILayout.Space(24);
+                    Color backup = GUI.color;
+                    bool isLocked = LinkGameView.LockedSceneView == sceneView;
+
+
+                    if(isLinked && isLocked)
+                    {
+                        GUI.color = Color.green *2;
+                    }
+
                     isLinked = GUILayout.Toggle(isLinked, Contents.linkGameView, EditorStyles.toolbarButton, GUILayout.Width(64));
 
                     if (GUI.changed)
 
-                    bool isLocked = LinkGameView.LockedSceneView == sceneView;
                     isLocked = GUILayout.Toggle(isLocked, Contents.lockLinkGameView, EditorStyles.toolbarButton);
 
                     if (GUI.changed)
                             LinkGameView.LockedSceneView = null;
                         }
                     }
+
+                    GUI.color = backup;
 
                     GUILayout.FlexibleSpace();