context: // 
  // MenuItemBackend.cs
  //  
  // Author:
  //       Lluis Sanchez <lluis@xamarin.com>
  // 
  // Copyright (c) 2011 Xamarin Inc
  // 
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  // 
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  // 
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  using System;
  using Xwt.Backends;
  using Xwt.Drawing;
  using System.Collections.Generic;
  
  
  namespace Xwt.GtkBackend
  {
  	public class MenuItemBackend: IMenuItemBackend
  	{
  		IMenuItemEventSink eventSink;
  		Gtk.MenuItem item;
  		Gtk.Label label;
  		List<MenuItemEvent> enabledEvents;
  		bool changingCheck;
  		ApplicationContext context;
  		
  		public MenuItemBackend ()
  			: this (new Gtk.ImageMenuItem (""))
  		{
  		}
  		
  		public MenuItemBackend (Gtk.MenuItem item)
  		{
  			this.item = item;
  			label = (Gtk.Label) item.Child;
  			item.ShowAll ();
  		}
  		
  		public Gtk.MenuItem MenuItem {
  			get { return item; }
  		}
  
  		public void Initialize (IMenuItemEventSink eventSink)
  		{
  			this.eventSink = eventSink;
  		}
  
  		public void SetSubmenu (IMenuBackend menu)
  		{
  			if (menu == null)
  				item.Submenu = null;
  			else {
  				Gtk.Menu m = ((MenuBackend)menu).Menu;
  				item.Submenu = m;
  			}
  		}
  
  		ImageDescription? defImage, selImage;
  
  		public void SetImage (ImageDescription image)
  		{
  			Gtk.ImageMenuItem it = item as Gtk.ImageMenuItem;
  			if (it == null)
  				return;
  			if (!image.IsNull) {
  				if (defImage == null)
  					item.StateChanged += ImageMenuItemStateChanged;
  				defImage = image;
  				selImage = new ImageDescription {
  					Backend = image.Backend,
  					Size = image.Size,
  					Alpha = image.Alpha,
  					Styles = image.Styles.Add ("sel")
  				};
  				var img = new ImageBox (context, image);
  				img.ShowAll ();
  				it.Image = img;
  				GtkWorkarounds.ForceImageOnMenuItem (it);
  			} else {
  				if (defImage.HasValue) {
  					item.StateChanged -= ImageMenuItemStateChanged;
  					defImage = selImage = null;
  				}
  				it.Image = null;
  			}
  		}
  
  		void ImageMenuItemStateChanged (object o, Gtk.StateChangedArgs args)
  		{
  			var it = item as Gtk.ImageMenuItem;
  			var image = it?.Image as ImageBox;
  			if (image == null || selImage == null || defImage == null)
  				return;
  			if (it.State == Gtk.StateType.Prelight)
  				image.Image = selImage.Value;
  			else if (args.PreviousState == Gtk.StateType.Prelight)
  				image.Image = defImage.Value;
  		}
  
  		public string Label {
  			get {
  				return label != null ? (label.UseUnderline ? label.LabelProp : label.Text) : "";
  			}
  			set {
  				if (label.UseUnderline)
  					label.TextWithMnemonic = value;
  				else
  					label.Text = value;
  			}
  		}
  
  		public string TooltipText {
  			get {
  				return item.TooltipText;
  			}
  			set {
  				item.TooltipText = value;
  			}
  		}
  
  		public bool UseMnemonic {
  			get { return label.UseUnderline; }
  			set { label.UseUnderline = value; }
  		}
  		
  		public bool Sensitive {
  			get {
  				return item.Sensitive;
  			}
  			set {
  				item.Sensitive = value;
  			}
  		}
  		
  		public bool Visible {
  			get {
  				return item.Visible;
  			}
  			set {
  				item.Visible = value;
  			}
  		}
  		
  		public bool Checked {
  			get { return (item is Gtk.CheckMenuItem) && ((Gtk.CheckMenuItem)item).Active; }
  			set {
  				if (item is Gtk.CheckMenuItem) {
  					changingCheck = true;
  					((Gtk.CheckMenuItem)item).Active = value;
  					changingCheck = false;
  				}
  			}
  		}
  		
  /*		public void SetType (MenuItemType type)
  		{
  			string text = label.Text;
  			
  			Gtk.MenuItem newItem = null;
  			switch (type) {
  			case MenuItemType.Normal:
  				if (!(item is Gtk.ImageMenuItem))
  					newItem = new Gtk.ImageMenuItem (text);
  				break;
  			case MenuItemType.CheckBox:
  				if (item.GetType () != typeof(Gtk.CheckMenuItem))
  					newItem = new Gtk.CheckMenuItem (text);
  				break;
  			case MenuItemType.RadioButton:
  				if (!(item is Gtk.RadioMenuItem))
  					newItem = new Gtk.RadioMenuItem (text);
  				break;
  			}
  			
  			if (newItem != null) {
  				if ((newItem is Gtk.CheckMenuItem) && (item is Gtk.CheckMenuItem))
  					((Gtk.CheckMenuItem)item).Active = ((Gtk.CheckMenuItem)newItem).Active;
  				newItem.Sensitive = item.Sensitive;
  				if (item.Parent != null) {
  					Gtk.Menu m = (Gtk.Menu)item.Parent;
  					int pos = Array.IndexOf (m.Children, item);
  					m.Insert (newItem, pos);
  					m.Remove (item);
  				}
  				newItem.ShowAll ();
  				if (!item.Visible)
  					newItem.Hide ();
  				
  				if (enabledEvents != null) {
  					foreach (var ob in enabledEvents)
  						DisableEvent (ob);
  				}
  				
  				item = newItem;
  				label = (Gtk.Label) item.Child;
  				
  				if (enabledEvents != null) {
  					foreach (var ob in enabledEvents)
  						EnableEvent (ob);
  				}
  			}
  		}*/
  		
  		public void InitializeBackend (object frontend, ApplicationContext context)
  		{
  			this.context = context;
  		}
  
  		public void EnableEvent (object eventId)
  		{
  			if (eventId is MenuItemEvent) {
  				if (enabledEvents == null)
  					enabledEvents = new List<MenuItemEvent> ();
  				enabledEvents.Add ((MenuItemEvent)eventId);
  				if ((MenuItemEvent)eventId == MenuItemEvent.Clicked)
  					item.Activated += HandleItemActivated;
  			}
  		}
  
  		public void DisableEvent (object eventId)
  		{
  
gt: 			if (eventId is MenuItemEvent) {