[Reg] Qt 6 ignores the "frameShape" selector when styling a QFrame with CSS

When using the Fusion style, a QFrame with QFrame::HLine or QFrame::VLine set as the frameShape is displayed as a 1 px solid black line both for Qt 5.15 and Qt 6.2.

Up to Qt 5.15, it was possible to style the appearance of such a QFrame with CSS, e.g. via 

QApplication app(argc, argv);
app.setStyleSheet(QStringLiteral(
    "QFrame[frameShape=\"4\"],"
    "QFrame[frameShape=\"5\"] { "
        "color: palette(Mid); "
    "}"));

which e.g. lead to the QFrame being painted as a gray line in this case.

Qt 6 (I tested this with Qt 6.2.3) seems to ignore the frameShape selector. Nothing changes, no matter if the style sheet is set or not: in both cases the QFrame appears as a 1px solid black line.

QFrame's Shape enum seems to be unchanged since Qt 5.15. I also tried to use other representations of the set value in the selector like frameShape=\"0x0004\" or frameShape=\"QFrame::HLine\", but none worked.

See the attached minimal example and the result screenshots.