QWidget don't change color theme on macOS under specific circumstance

[Sky Lian]

Qt 6.5.0
macOS 13.2.1

int main(int argc, char **argv) {
    QApplication a(argc, argv);

    QScrollarea window;
    QWidget widget;
    QGridLayout layout(&widget);

    widget.setStyleSheet(R"--(.QLabel[wordWrap="false"]:focus {
        border-radius: 12px;
        border: 8px solid rgb(22, 185, 255);
    })--"); // I know widget has no QLabel children; some valid stylesheet is the point
    window.setWidget(&widget);
    window.show();
    return a.exec();
}

Run, change appearance in system setting, and then:

[SGaist]

Hi,

Just an educated guess: setting a stylesheet triggers the use of a different style which replaces the one that mimics the system thus it might not be theme aware.

[Sky Lian]

@SGaist
There're another 2 necessary factors beside stylesheet: QScrollArea & QGridLayout.

And another observation: go through it: print widget and window palette's rgb, delay printing to 3s later, and switch appearance; you will find that widget palette's RGB hasn't changed, but window palette's has.