private void AddLayerClicked(object sender, EventArgs e)
 {
     // For now all layers are assumed to be some type of image file.
     if (openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
     {
         // Load the image in as a new layer.
         Layer layer = new Layer("Layer " + _layerListView.Items.Count);
         if (_textureManager.Exists(openFileDialog1.FileName) == false)
         {
             _textureManager.LoadTexture(openFileDialog1.FileName, openFileDialog1.FileName);
         }
         layer.SetImage(_textureManager.Get(openFileDialog1.FileName));
         _scene.AddLayer(layer);
         ListViewItem listViewItem = new ListViewItem();
         listViewItem.Text = "Layer " + _layerListView.Items.Count;
         listViewItem.Name = "someuniqueid";
         _layerListView.Items.Add(listViewItem);
     }
 }