ArrayGUI

using UnityEngine;
using System.Collections;
using UnityEditor;

[CustomEditor(typeof(Array))]
public class ArrayGUI : Editor
{
    public override void OnInspectorGUI()
    {
        GUILayout.Label ("Label text");
        DrawDefaultInspector ();
        Array ar = (Array)target;
        if (GUILayout.Button ("Instantiate"))
        {
            ar.CreateArray();
        }

    }
}