QToolButton in QToolBar checked, in dark mode not rendered properly

QToolButtons in a QToolBar which are checked do not render properly – they try to render darker to show their selected state, but instead should render lighter so that they can be seen against the black.

Workaround for this is to use Stylesheets to set colors, but stylesheets for QToolBar has also a bug (https://bugreports.qt.io/browse/QTBUG-12717) and the workaround for that is to define border color to QToolBar for the style sheets to have any effect.