AlphaSelfIllum shader can see through textrues

Questions & Answers
1

This is the shader I'm trying to use:

http://www.unifycommunity.com/wiki/index.php?title=AlphaSelfIllum

The code:

Shader "My Shaders/AlphaSelfIllum" {
    Properties {
        _Color ("Color Tint", Color) = (1,1,1,1)
        _MainTex ("SelfIllum Color (RGB) Alpha (A)", 2D) = "white"
    }
    Category {
       Lighting On
       ZWrite Off
       Cull Back
       Blend SrcAlpha OneMinusSrcAlpha
       Tags {Queue=Transparent}
       SubShader {
            Material {
               Emission [_Color]
            }
            Pass {
               SetTexture [_MainTex] {
                      Combine Texture * Primary, Texture * Primary
                }
            }
        } 
    }
}

this is perfect for what I'm doing because it's a flat texture only shader and it has alpha. but my problem is that if i'm using the material on multiple objects that're in front of each other, I can see through some of them. So if I apply this material to three planes, I can see texture on the plane behind it through the plane in front of it.. This doesn't happen in all cases, so I'm not quite sure what's going on.. any help would be highly appreciated

2

That shader is using ZWrite Off, so it's not writing to the depth buffer.