Why tilling property for Costume Shaders is not working ?

Any one can help ?

 Shader "Nadeem/BlendTwoImages"
 {
      Properties
     {
         [PerRendererData]_MainTex ("Sprite Texture", 2D) = "white" {}
         _MainMask ("Main Mask", 2D) = "white" {}
         _Color ("Tint", Color) = (1,1,1,1)
         [MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
         _TexSize ("Texture Size", Float) = 512
  
     }
  
     SubShader
     {
     Tags
         {
             "Queue"="Transparent"
             "IgnoreProjector"="True"
             "RenderType"="Transparent"
             "PreviewType"="Plane"
             "CanUseSpriteAtlas"="True"
         }
  
         Cull Off
         Lighting Off
         ZWrite Off
         Blend One OneMinusSrcAlpha
         Pass
         {
         CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
             #pragma target 2.0
             #pragma multi_compile _ PIXELSNAP_ON
             #pragma multi_compile _ ETC1_EXTERNAL_ALPHA
             #include "UnityCG.cginc"
            
             struct appdata_t
             {
                 float4 vertex   : POSITION;
                 float4 color    : COLOR;
                 float2 texcoord : TEXCOORD0;
             };
  
             struct v2f
             {
                 float4 vertex   : SV_POSITION;
                 fixed4 color    : COLOR;
                 float2 texcoord  : TEXCOORD0;
             };
            
             fixed4 _Color;
  
             v2f vert(appdata_t IN)
             {
                 v2f OUT;
 
                 OUT.vertex = UnityObjectToClipPos(IN.vertex);
                 OUT.texcoord = IN.texcoord;
                 OUT.color = IN.color * _Color;
                 #ifdef PIXELSNAP_ON
                 OUT.vertex = UnityPixelSnap (OUT.vertex);
                 #endif
  
                 return OUT;
             }
  
             sampler2D _MainTex;
             sampler2D _AlphaTex;
             sampler2D _MainMask;
             fixed4 SampleSpriteTexture (float2 uv)
             {
 
                 fixed4 color = tex2D (_MainTex, uv);
                 fixed4 cloud = tex2D (_MainMask, uv);
                 color *= cloud;
  
 #if ETC1_EXTERNAL_ALPHA
                 // get the color from an external texture (usecase: Alpha support for ETC1 on android)
                 
                 color.a = tex2D (_AlphaTex, uv).r;
 #endif //ETC1_EXTERNAL_ALPHA
  
                 return color;
             }
  
             fixed4 frag(v2f IN) : SV_Target
             {
                 fixed4 c = SampleSpriteTexture (IN.texcoord) * IN.color;
  
                 c.rgb *= c.a;
                 return c;
             }
         ENDCG
         }
     }
 }