private void Button_MouseLeave(object sender, MouseEventArgs e)
{
Grid g = (Grid)sender;
TextBlock tb = (TextBlock)(g.Children[1]);
var bc = new BrushConverter();
tb.Foreground = (Brush)bc.ConvertFromString("#aaaaaa");
Image collapseIcon = (Image)g.Children[0];
// Change the collapse icon and rotate
var imageUri = new Uri(@"pack://application:,,,/DynamoCoreWpf;component/UI/Images/expand_normal.png");
BitmapImage hover = new BitmapImage(imageUri);
collapseIcon.Source = hover;
}