Show lag when using NSPopupButton

MenuViewController.cs

// Mod the macControls sample project to show the UI lag when using some UI elements

// This file has been autogenerated from a class added in the UI designer.

using System;

using Foundation;
using AppKit;
using MetalKit;
using CoreGraphics;
using Metal;
using System.Diagnostics;

namespace MacControls
{
	public partial class MenuViewController : NSViewController, IMTKViewDelegate
    {
        MTKView mtlView;
        Stopwatch stopwatch = new Stopwatch();
        public void Draw(MTKView view)
        {
            FeedbackLabel.StringValue = stopwatch.Elapsed.TotalSeconds.ToString();
            stopwatch.Restart();
        }
        public void DrawableSizeWillChange(MTKView view, CGSize size)
        {
            //throw new NotImplementedException();
        }
        void InitMetal()
        {
            mtlView = new MTKView(new CGRect(0, 0, 10, 10), MTLDevice.SystemDefault);
            mtlView.Delegate = this;
            mtlView.ClearColor = new MTLClearColor(1, 0, 0, 1);
            View.AddSubview(mtlView);
            stopwatch.Start();
        }

        #region Constructors
        public MenuViewController (IntPtr handle) : base (handle)
		{
		}
        #endregion

        #region Override Methods
        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            InitMetal();
        }

        public override void ViewWillAppear ()
		{
			base.ViewWillAppear ();
		}
		#endregion

		#region Actions
		partial void ItemOne (Foundation.NSObject sender) {
			DropDownSelected.Title = "Item 1";
			FeedbackLabel.StringValue = "Item One Selected";
		}

		partial void ItemTwo (Foundation.NSObject sender) {
			DropDownSelected.Title = "Item 2";
			FeedbackLabel.StringValue = "Item Two Selected";
		}

		partial void ItemThree (Foundation.NSObject sender) {
			DropDownSelected.Title = "Item 3";
			FeedbackLabel.StringValue = "Item Three Selected";
		}


        #endregion
    }
}