[Logical Error] Select a game object and perform actions using GUI.Button

I am currently working on a strategy game and I want to preform actions using GUI.Button on game objects. I am using ray cast and mouse click to select the object however when I click on GUI.Button to take out another action the button disappears. I want to use that button to open up another GUI.Box to show some descriptions.

I know why the button is disappearing, it is because I am projecting the ray cast to my button clicks in the update function but how can I avoid this? should I use another way of selecting objects instead of ray cast or else?

Here is my script:

 #pragma strict
 @HideInInspector
 var isCalled:int = 0;
 @HideInInspector
 var scWidth:int = 0;
 @HideInInspector
 var scHeight:int = 0;
 function Start () {
     scWidth = Screen.width;
     scHeight = Screen.height;        
 }
 
 function Update () {
 if (Input.GetMouseButtonDown(0)) {
          var ray : Ray = Camera.main.ScreenPointToRay (Input.mousePosition);
          var hit : RaycastHit;
          if (Physics.Raycast (ray, hit)) {
              if (hit.collider.tag == "House") {
              isCalled = 1;
             } else{
              isCalled = 0;
              }
           }
      }
 }
 
 function OnGUI(){
 if(isCalled==1)
 GUI.Button(Rect(scWidth/2,(scHeight/2)+(scHeight/4),120,120), name);
 }