#include <QApplication>
#include <QDockWidget>
#include <QLabel>
#include <QMainWindow>

QDockWidget* ShowDockWidget(QString name, QWidget *parent)
{
    QDockWidget* dock = new QDockWidget(parent);
    QLabel *title = new QLabel(name, dock);
    title->setStyleSheet("background-color: red");
    dock->setWindowTitle(name);
    dock->setTitleBarWidget(title);
    dock->setContextMenuPolicy(Qt::ContextMenuPolicy::CustomContextMenu);
    dock->setAttribute(Qt::WA_DeleteOnClose);
    dock->setWidget(new QLabel("Content"));
    QObject::connect(dock, &QWidget::customContextMenuRequested, [dock](const QPoint& /*pos*/)
             {
                 dock->setFloating(true);
                 dock->move(dock->pos() + QPoint(100,100));
             });

    return dock;
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QMainWindow w;
    w.setDocumentMode(false);
    w.setTabPosition(Qt::AllDockWidgetAreas, QTabWidget::North);
    w.setDockOptions(QMainWindow::AllowNestedDocks | QMainWindow::AllowTabbedDocks | QMainWindow::GroupedDragging);
    w.setGeometry(50,50,600,400);
    QDockWidget *d1 = ShowDockWidget("Dock1", &w);
    QDockWidget *d2 = ShowDockWidget("Dock2", &w);
    w.addDockWidget(Qt::RightDockWidgetArea,d1);
    w.addDockWidget(Qt::RightDockWidgetArea,d2);
    w.tabifyDockWidget(d1,d2);
    w.show();
    return a.exec();
}