#include <QApplication>
#include <QDialog>
#include <QPushButton>
#include <QTextEdit>
#include <QVBoxLayout>
#include <QFrame>
#include <QContextMenuEvent>

class Popup : public QFrame {
public:
    Popup(QWidget *parent = nullptr) : QFrame(parent, Qt::Popup) {
        QVBoxLayout *layout = new QVBoxLayout(this);
        textEdit = new QTextEdit(this);
        layout->addWidget(textEdit);
        setFixedSize(300, 200);
    }

private:
    QTextEdit *textEdit;
};

class MainWindow : public QDialog {
public:
    MainWindow() {
        setFixedSize(300, 300);
        QVBoxLayout *layout = new QVBoxLayout(this);
        
        button = new QPushButton("Popup", this);
        connect(button, &QPushButton::clicked, this, &MainWindow::showPopup);
        
        layout->addWidget(button);
        
        popup = new Popup(this);
    }

private slots:
    void showPopup() {
        popup->move(button->mapToGlobal(button->rect().bottomLeft()));
        popup->show();
    }

private:
    QPushButton *button;
    Popup *popup;
};

int main(int argc, char *argv[]) {
    QApplication app(argc, argv);
    MainWindow window;
    window.show();
    return app.exec();
}