if texture used from class it does not show in game, advice needed?

here is the test class i made:

class Button extends Object{

 //VARIABLES
 var x:int;
 var y:int;
 var w:int;
 var h:int;

 var texture:Texture2D;

 //CONSTRUCTOR
 function Button(){

     x=10;
     y=10;
     w=30;
     h=30;

 }

 function Show(){

     if(GUI.Button(Rect(x,y,w,h),texture)){

         Debug.Log("Button Pressed!");

     }   
 }

slot for texture appears when i create the object in other script. here is how i did it:

var TestButton : Button;

then in the OnGUI function i just type this:

TestButton.Show();

the button shows and it works but texture is not there but i put it in the slot from the inspector, what i am doing wrong?

here is the screenshot: