1. how to change the frame of an animation
2. keyboard interaction
3. scrollable background
4. hit test (interaction) on objects

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Shapes;

namespace HitTest
{
    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();

            Loaded += new RoutedEventHandler(MainPage_Loaded);
        }

        void MainPage_Loaded(object sender, RoutedEventArgs e)
        {
            App.Current.RootVisual.MouseLeftButtonDown += new MouseButtonEventHandler(RootVisual_MouseLeftButtonDown);
        }

        void RootVisual_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            List<uielement> list = VisualTreeHelper.FindElementsInHostCoordinates
            (e.GetPosition(null), LayoutRoot as UIElement) as List<uielement>;

            var selectedControls = from control in list
                                   where control is Rectangle
                                   select control as Rectangle;

            if (selectedControls.Count() &gt; 0)
            {
                foreach (var selectedControl in selectedControls)
                {
                    // do your opreation here
                }
            }
        }
    }
}