public WidgetFocus()
        {
            var       text   = new TextEntry();
            var       check  = new CheckBox("CheckBox");
            var       slider = new HSlider();
            ListStore store  = new ListStore(value);
            var       list   = new ListView(store);

            list.Columns.Add("Value", value);
            list.HeadersVisible = false;
            for (int n = 0; n < 10; n++)
            {
                var r = store.AddRow();
                store.SetValue(r, value, "Value " + n);
            }

            var btn1 = new Button("TextEnty");
            var btn2 = new Button("Checkbox");
            var btn3 = new Button("Slider");
            var btn4 = new Button("ListBox");
            var btn5 = new Button("Button");

            btn1.Clicked += (sender, e) => text.SetFocus();
            btn2.Clicked += (sender, e) => check.SetFocus();
            btn3.Clicked += (sender, e) => slider.SetFocus();
            btn4.Clicked += (sender, e) => list.SetFocus();
            btn5.Clicked += (sender, e) => btn1.SetFocus();

            var btnBox = new HBox();

            btnBox.PackStart(btn1);
            btnBox.PackStart(btn2);
            btnBox.PackStart(btn3);
            btnBox.PackStart(btn4);
            btnBox.PackStart(btn5);

            var focusBox = new HBox();
            var vbox     = new VBox();

            vbox.PackStart(text);
            vbox.PackStart(check);
            vbox.PackStart(slider);
            focusBox.PackStart(vbox);
            focusBox.PackStart(list, true);

            PackStart(btnBox);
            PackStart(focusBox, true);
        }