A CustomEditor can be defined for your shader. When you do this Unity will look for a class that extends ShaderGUI with this name. If one is found any material that uses this shader will use this ShaderGUI. See Custom Shader GUI for examples.
CustomEditor "name"
Use the ShaderGUI with a given name.
A CustomEditor statement effects all materials that use this Shader
Shader "example" {
// properties and subshaders here...
CustomEditor "MyCustomEditor"
}