A script for drawing horizontal lines inside of the Unity Editor

EditorGuiUtility.cs

#if UNITY_EDITOR
using UnityEditor;
using UnityEngine;

public static class EditorGuiUtility
{
  public static void DrawUILine(Color color, int thickness = 2, int padding = 10)
  {
    Rect r = EditorGUILayout.GetControlRect(GUILayout.Height(padding+thickness));
    r.height = thickness;
    r.y+=padding/2;
    r.x-=2;
    r.width +=6;
    EditorGUI.DrawRect(r, color);
  }

}
#endif