private void MainCanvas_MouseDown(object sender, MouseButtonEventArgs e)
        {
            LastPoint = Mouse.GetPosition(MainCanvas);

            if (drawInProgress)
            {
                Box = new BoundingBox(MainCanvas, LastPoint);
                boxes.Add(Box);
            }
            else
            {
                if (Box != null && Box.CheckAdornerHit(LastPoint))
                {
                    // resizing exiting box
                    resizeInProgress = true;
                }
                else if (Box != null && Box.SelectTest(LastPoint))
                {
                    // moving box
                }
                else
                {
                    foreach (var mainCanvasChild in boxes)
                    {
                        mainCanvasChild.SelectTest(LastPoint);
                    }

                    var selectedItems = boxes.Where(x => x.IsSelected);

                    if (selectedItems.Any())
                    {
                        if (selectedItems.Count() > 1)
                        {
                            var itemsToUnselect = selectedItems.Reverse().Skip(1);

                            foreach (var boundingBox in itemsToUnselect)
                            {
                                boundingBox.UnSelect();
                            }
                        }

                        Box = selectedItems.First();
                    }
                    else
                    {
                        Box = null;
                    }
                }
            }
        }