When I try to call the dialog, the dialog box is created but not displayed. The interface is also blocked (you cannot close the window for example): (select color window)

in the sample library everything works as it should:

I changed the library code and added a flag QColorDialog::DontUseNativeDialog

void ColorDialogButton::buttonClicked()
{
    auto color = QColorDialog::getColor(Qt::white, this, QString(), QColorDialog::DontUseNativeDialog | getColorDialogOptions());
    emit colorSelected(color);
}

and it helped:

I want to understand why this is happening. Perhaps I'm adding the color widget incorrectly?
Some code for understanding what's going on:

color picker example:

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    auto widget = new QWidget();
    widget->setFixedWidth(200);
    widget->setFixedHeight(200);
    auto layout = new QVBoxLayout();
    auto colorPicker = new KColorPicker(true);
    colorPicker->setColor(QColor(Qt::red));
    layout->addWidget(colorPicker);
    widget->setLayout(layout);
    widget->show();

    return app.exec();
}

my code:

SettingsWindow::SettingsWindow(MainWindow* wm, QWidget* parent)
...
    , colorsTab_(new QWidget)
    , colors_(new ColorsWidget(colorsTab_))
...
{
   ...

    // colors
    auto* colorsLayout = new QVBoxLayout(colorsTab_);
    colorsTab_->setLayout(colorsLayout);
    colorsLayout->addWidget(colors_);
    tabWidget_->addTab(colorsTab_, tr("Colors"));

 ...
}

ColorsWidget::ColorsWidget(QWidget* parent)
    : QWidget(parent)
    , layout_(new QVBoxLayout(this))
{
    layout_->setAlignment(Qt::AlignTop);
    auto colorPicker = new KColorPicker(true);
    colorPicker->setColor(QColor(Qt::red));
    layout_->addWidget(colorPicker);
    setLayout(layout_);
}

regards, max