How do I add a drop-down menu to an EditorWindow?

I found that a mixed of the above answers was required to get the editor-style menu strip at the top of an EditorWindow:

 void OnGUI() {
     GUILayout.BeginHorizontal(EditorStyles.toolbar);

     DrawToolStrip();

     GUILayout.EndHorizontal();
 }

 void DrawToolStrip() {
     if (GUILayout.Button("Create...", EditorStyles.toolbarButton)) {
         OnMenu_Create();
         EditorGUIUtility.ExitGUI();
     }

     GUILayout.FlexibleSpace();

     if (GUILayout.Button("Tools", EditorStyles.toolbarDropDown)) {
         GenericMenu toolsMenu = new GenericMenu();

         if (Selection.activeGameObject != null)
             toolsMenu.AddItem(new GUIContent("Optimize Selected"), false, OnTools_OptimizeSelected);
         else
             toolsMenu.AddDisabledItem(new GUIContent("Optimize Selected"));

         toolsMenu.AddSeparator("");

         toolsMenu.AddItem(new GUIContent("Help..."), false, OnTools_Help);

         // Offset menu from right of editor window
         toolsMenu.DropDown(new Rect(Screen.width - 216 - 40, 0, 0, 16));
         EditorGUIUtility.ExitGUI();
     }
 }

 void OnMenu_Create() {
     // Do something!
 }

 void OnTools_OptimizeSelected() {
     // Do something!
 }

 void OnTools_Help() {
     Help.BrowseURL("http://example.com/product/help");
 }

Ok, I refer this a newbie question but as a developer state, and not as newbie question in general. I'm also still considered as noobs!

Here I will create a menu that will automatically added into your Unity.

Unity JavaScript - JS

Create new folder and rename it as "Editor"

On the folder you just create right click and Create > JavaScript

There will be a new file and rename it as "SemutMenu"

Right click the newly created and renamed file to edit it (choose edit).

Withing your editor, clear all then copy and paste below code..

import System.IO; class SemutMenu extends EditorWindow {

@MenuItem ("Semut/Menu One")
static function ShowWindow () {
    EditorWindow.GetWindow (SemutMenu);
}

}

Now after you SAVE IT, you will have new menu that appear on the Semut > Menu One

That will be all!