UpdateShaders in Editor

Internal-GUITextureClipText.shader

// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)


Shader "Hidden/Internal-GUITextureClipText"
{
    Properties { _MainTex ("Texture", 2D) = "white" {} }

    CGINCLUDE
    #pragma vertex vert
    #pragma fragment frag
    #pragma target 2.0

    #include "UnityCG.cginc"

    struct appdata_t {
        float4 vertex : POSITION;
        fixed4 color : COLOR;
        float2 texcoord : TEXCOORD0;
        UNITY_VERTEX_INPUT_INSTANCE_ID
    };

    struct v2f {
        float4 vertex : SV_POSITION;
        fixed4 color : COLOR;
        float2 texcoord : TEXCOORD0;
        float2 clipUV : TEXCOORD1;
        UNITY_VERTEX_OUTPUT_STEREO
    };

    sampler2D _MainTex;
    sampler2D _GUIClipTexture;

    uniform float4 _MainTex_ST;
    uniform fixed4 _Color;
    uniform float4x4 unity_GUIClipTextureMatrix;

	uniform fixed4 _editorColor2;

    v2f vert (appdata_t v)
    {
        v2f o;
        UNITY_SETUP_INSTANCE_ID(v);
        UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
        o.vertex = UnityObjectToClipPos(v.vertex);
        float3 eyePos = UnityObjectToViewPos(v.vertex);
        o.clipUV = mul(unity_GUIClipTextureMatrix, float4(eyePos.xy, 0, 1.0));
       // o.color = v.color * _Color;
        o.color = fixed4(_editorColor2.rgb,v.color.a);
        o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex);
        return o;
    }

    fixed4 frag (v2f i) : SV_Target
    {
        fixed4 col = i.color;
        col.a *= tex2D(_MainTex, i.texcoord).a * tex2D(_GUIClipTexture, i.clipUV).a;
        return col;
    }
    ENDCG

    SubShader {
        Tags { "ForceSupported" = "True" }

        Lighting Off
        Blend SrcAlpha OneMinusSrcAlpha, One One
        Cull Off
        ZWrite Off
        ZTest Always

        Pass {
            CGPROGRAM
            ENDCG
        }
    }

    SubShader {
        Tags { "ForceSupported" = "True" }

        Lighting Off
        Blend SrcAlpha OneMinusSrcAlpha
        Cull Off
        ZWrite Off
        ZTest Always

        Pass {
            CGPROGRAM
            ENDCG
        }
    }
}

UpdateShaders.cs

using UnityEngine;

[ExecuteInEditMode]
public class UpdateShaders : MonoBehaviour
{

    void OnDrawGizmos()
    {
        Debug.Log("SkinMode : Pro9000");
        Shader.SetGlobalColor("_editorColor", Random.ColorHSV(0, 1, 0, 1, 0, 1, 1, 1));
        Shader.SetGlobalColor("_editorColor2", Random.ColorHSV(0, 1, 0, 1, 0, 1, 1, 1));
    }
}