disabled MiniSplitter looks enabled

I'd like to change the color when it is disabled. How can I improve the code below?

(Just setting alpha to 64 seems okay to me visually)

void MiniSplitterHandle::paintEvent(QPaintEvent *event)
{
    QPainter painter(this);
    const QColor color = Utils::creatorTheme()->color(
                m_lightColored ? Utils::Theme::FancyToolBarSeparatorColor
                               : Utils::Theme::SplitterColor);
    painter.fillRect(event->rect(), color);
}