ComboBox multiple fixes

Example/demo.cs

@@ -449,20 +449,22 @@ static void ListSelectionDemo (bool multiple)
 
 	static void ComboBoxDemo ()
 	{
-		IList<string> items = new List<string> ();
-		foreach (var dir in new [] { "/etc", @"\windows\System32" }) {
+		//TODO: Duplicated code in ListsAndCombos.cs Consider moving to shared assembly
+		var items = new List<ustring> ();
+		foreach (var dir in new [] { "/etc", @$"{Environment.GetEnvironmentVariable ("SystemRoot")}\System32" }) {
 			if (Directory.Exists (dir)) {
 				items = Directory.GetFiles (dir).Union (Directory.GetDirectories (dir))
 					.Select (Path.GetFileName)
 					.Where (x => char.IsLetterOrDigit (x [0]))
-					.OrderBy (x => x).ToList ();
+					.OrderBy (x => x).Select (x => ustring.Make (x)).ToList ();
 			}
 		}
-		var list = new ComboBox () { X = 0, Y = 0, Width = Dim.Fill(), Height = Dim.Fill() };
-		list.SetSource(items.ToList());
-		list.SelectedItemChanged += (object sender, ustring text) => { Application.RequestStop (); };
+		var list = new ComboBox () { Width = Dim.Fill(), Height = Dim.Fill() };
+		list.SetSource(items);
+		list.OpenSelectedItem += (ListViewItemEventArgs text) => { Application.RequestStop (); };
 
-		var d = new Dialog ("Select source file", 40, 12) { list };
+		var d = new Dialog () { Title = "Select source file", Width = Dim.Percent (50), Height = Dim.Percent (50) };
+		d.Add (list);
 		Application.Run (d);
 
 		MessageBox.Query (60, 10, "Selected file", list.Text.ToString() == "" ? "Nothing selected" : list.Text.ToString(), "Ok");

Terminal.Gui/Core/View.cs

@@ -124,6 +124,16 @@ internal enum Direction {
 
 		TextFormatter viewText;
 
+		/// <summary>
+		/// Event fired when a subview is being added to this view.
+		/// </summary>
+		public Action<View> Added;
+
+		/// <summary>
+		/// Event fired when a subview is being removed from this view.
+		/// </summary>
+		public Action<View> Removed;
+
 		/// <summary>
 		/// Event fired when the view gets focus.
 		/// </summary>
@@ -552,6 +562,7 @@ public virtual void Add (View view)
 				subviews = new List<View> ();
 			subviews.Add (view);
 			view.container = this;
+			OnAdded (view);
 			if (view.CanFocus)
 				CanFocus = true;
 			SetNeedsLayout ();
@@ -601,6 +612,7 @@ public virtual void Remove (View view)
 			var touched = view.Frame;
 			subviews.Remove (view);
 			view.container = null;
+			OnRemoved (view);
 
 			if (subviews.Count < 1)
 				this.CanFocus = false;
@@ -933,6 +945,24 @@ public FocusEventArgs () { }
 			public bool Handled { get; set; }
 		}
 
+		/// <summary>
+		/// Method invoked  when a subview is being added to this view.
+		/// </summary>
+		/// <param name="view">The subview being added.</param>
+		public virtual void OnAdded (View view)
+		{
+			view.Added?.Invoke (this);
+		}
+
+		/// <summary>
+		/// Method invoked when a subview is being removed from this view.
+		/// </summary>
+		/// <param name="view">The subview being removed.</param>
+		public virtual void OnRemoved (View view)
+		{
+			view.Removed?.Invoke (this);
+		}
+
 		/// <inheritdoc/>
 		public override bool OnEnter ()
 		{