GameObject deactivate but don't activate again

Hi, the GameObjects deactivate correctly, but after I deactivate them, they don't activate again. Anyone?

 function OnGUI () {
    
     GUI.Box (Rect (10,10,100,90), "LOD Menu");
 
     
     if (GUI.Button (Rect (20,40,80,20), "LOD100")) {
         for(var lod400 : GameObject in GameObject.FindGameObjectsWithTag("LOD400"))
             {
                     lod400.active = false;
             }
         for(var lod100 : GameObject in GameObject.FindGameObjectsWithTag("LOD100"))
             {
                     lod100.active = true;
             }
     }
 
    
     if (GUI.Button (Rect (20,70,80,20), "LOD400")) {
         for(var lod400 : GameObject in GameObject.FindGameObjectsWithTag("LOD400"))
             {
                     lod400.active = true;
             }
         for(var lod100 : GameObject in GameObject.FindGameObjectsWithTag("LOD100"))
             {
                     lod100.active = false;
             }
     }
 }