#include <QtWidgets/QtWidgets>

class DockTitleWidget : public QWidget
{
  bool event(QEvent *e) override {
    return QWidget::event(e);
  }

  QSize sizeHint() const override {
    return QSize(300, 20);
  }

  QSize minimumSizeHint() const override {
    return sizeHint();
  }

  void paintEvent(QPaintEvent *) override {
    QPainter painter(this);
    painter.setPen(Qt::black);
    painter.fillRect(rect(), QBrush(Qt::red));
    painter.drawText(rect(), Qt::TextWordWrap | Qt::TextWrapAnywhere, "DockWidget w title");
  }
};

QString screenInfo(QScreen *s)
{
  if (!s) return "NULLPTR";
  QString out;
  QDebug outStream(&out);
  outStream << s << "dpr:" << s->devicePixelRatio() << "geometry:" << s->geometry();
  return out;
}

class XDockWidget : public QDockWidget
{
  using QDockWidget::QDockWidget;
};

int main(int argc, char *argv[])
{
  QApplication a(argc, argv);
  QMainWindow m;

  QScreen *s = QGuiApplication::screenAt(QPoint(2600, 700));
  if (s) {
    qDebug() << "Found screen";
  }
  else {
    qDebug() << "Didn't find screen";
  }

  m.setWindowTitle(QString("Main window") + QString(qVersion()));
  m.resize(600, 600);
  m.showMaximized();

  QWidget *centralWidget = new QWidget();
  QSizePolicy sp(QSizePolicy::Expanding, QSizePolicy::Expanding);
  centralWidget->setSizePolicy(sp);
  m.setCentralWidget(centralWidget);

  DockTitleWidget *titleWidget = new DockTitleWidget();
  XDockWidget *dockWdg = new XDockWidget(&m);
  dockWdg->setTitleBarWidget(titleWidget);
  m.addDockWidget(Qt::RightDockWidgetArea, dockWdg);

  QGroupBox *f = new QGroupBox();
  f->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
  dockWdg->setWidget(f);

  return a.exec();
}