#region Window: Resizing
    private void Resizing_MouseDown(object sender, MouseButtonEventArgs e) {
      var t = sender as Shape;
      if (t == null) { Debug.Assert(false); return; }
      t.CaptureMouse(); }
    private void Resizing_MouseUp(object sender, MouseButtonEventArgs e) {
      var t = sender as Shape;
      if (t == null) { Debug.Assert(false); return; }
      t.ReleaseMouseCapture(); }
    private void Resizing_WE(object sender, MouseEventArgs e) {
      var t = sender as Shape;
      if (t == null) { Debug.Assert(false); return; }
      if (!t.IsMouseCaptured) return;
      this.Width = Math.Max(e.GetPosition(this).X + 5, 0); }
    private void Resizing_EW(object sender, MouseEventArgs e) {
      var t = sender as Shape;
      if (t == null) { Debug.Assert(false); return; }
      if (!t.IsMouseCaptured) return;
      var x = e.GetPosition(this).X;
      var w = this.ActualWidth;
      this.Width = Math.Max(this.ActualWidth - x, 0);
      if (w != this.ActualWidth)
        this.Left += w - this.ActualWidth; }
    private void Resizing_NS(object sender, MouseEventArgs e) {
      var t = sender as Shape;
      if (t == null) { Debug.Assert(false); return; }
      if (!t.IsMouseCaptured) return;
      this.Height = Math.Max(e.GetPosition(this).Y + 5, 0); }
    private void Resizing_NWSE(object sender, MouseEventArgs e) {
      var t = sender as Shape;
      if (t == null) { Debug.Assert(false); return; }
      if (!t.IsMouseCaptured) return;
      var p = e.GetPosition(this);
      this.Width = Math.Max(p.X + 5, 0);
      this.Height = Math.Max(p.Y + 5, 0); }
    private void Resizing_NESW(object sender, MouseEventArgs e) {
      var t = sender as Shape;
      if (t == null) { Debug.Assert(false); return; }
      if (!t.IsMouseCaptured) return;
      var p = e.GetPosition(this);
      this.Height = Math.Max(p.Y + 5, 5);
      var w = this.ActualWidth;
      this.Width = Math.Max(this.ActualWidth - p.X, 5);
      if (w != this.ActualWidth)
        this.Left += w - this.ActualWidth; }
    #endregion