private void btnImage_Click(object sender, EventArgs e)
        {
#if DEMO
            new DemoVersionOnly("Changing background").ShowDialog();
#else
            ImageSelection images = new ImageSelection();
            if (DialogResult.OK == images.ShowDialog())
            {
                proj.UpdateBackground(images.SelectedItem.ImageId);
                proj.RefreshUI();
                proj.dirty = true;
            }
#endif
        }