private void ComboBox_DropDownClosed(object sender, EventArgs e)
        {
            var selectedTheme = new AppearanceViewModel().GetSelectedTheme();

            selectedTheme = ((FirstFloor.ModernUI.Presentation.Displayable)(selectedTheme)).DisplayName;
            if (selectedTheme.ToString() == "light")
            {
                var cb = (ComboBox)sender;
                cb.Foreground = Brushes.Black;
            }
            else
            {
                var cb = (ComboBox)sender;
                cb.Foreground = Brushes.WhiteSmoke;
            }
        }