normal:

QMenu* m_pContextMenu = new QMenu;
if(m_pContextMenu == NULL)
{
    return;
}

QAction *a1 = new QAction(QObject::tr("one"), this);
QAction *a2 = new QAction(QObject::tr("two"), this);
QAction *a3 = new QAction(QObject::tr("three"), this);
QAction *a4 = new QAction(QObject::tr("four"), this);
QAction *a5 = new QAction(QObject::tr("five"), this);
QAction *a6 = new QAction(QObject::tr("six"), this);
a1->setCheckable(true);
a1->setChecked(true);
a5->setCheckable(true);
a5->setChecked(true);

m_pContextMenu->addAction(a1);
m_pContextMenu->addAction(a2);
m_pContextMenu->addAction(a3);
m_pContextMenu->addAction(a4);
m_pContextMenu->addAction(a5);
m_pContextMenu->addAction(a6);
m_pContextMenu->move(400,300);
m_pContextMenu->show();

QMenu* m_pContextMenu = new QMenu;
if(m_pContextMenu == NULL)
{
    return;
}

//This setting results in an untidy layout

m_pContextMenu->setStyleSheet(
                              "padding: 5px 30px 5px 30px;"
                              "border: 1px solid transparent;"
                              "}");

QAction *a1 = new QAction(QObject::tr("one"), this);
QAction *a2 = new QAction(QObject::tr("two"), this);
QAction *a3 = new QAction(QObject::tr("three"), this);
QAction *a4 = new QAction(QObject::tr("four"), this);
QAction *a5 = new QAction(QObject::tr("five"), this);
QAction *a6 = new QAction(QObject::tr("six"), this);
a1->setCheckable(true);
a1->setChecked(true);
a5->setCheckable(true);
a5->setChecked(true);

m_pContextMenu->addAction(a1);
m_pContextMenu->addAction(a2);
m_pContextMenu->addAction(a3);
m_pContextMenu->addAction(a4);
m_pContextMenu->addAction(a5);
m_pContextMenu->addAction(a6);
m_pContextMenu->move(400,300);
m_pContextMenu->show();