class ItemBrandView : public QWidget
{
    Q_OBJECT

    protected:
        bool eventFilter(QObject *watched, QEvent *event);

    private:
        QTableView* table;

        QMenu* popupMenu;
        QLineEdit* finder;

...
};

void ItemBrandView::init()
{
...

    table = new QTableView();
    table->installEventFilter(this);

...

    finder = new QLineEdit(this);
    popupMenu = new QMenu(this);

    QWidgetAction* wFinder = new QWidgetAction(popupMenu);
    wFinder->setDefaultWidget(finder);

    popupMenu->addAction(wFinder);

};

bool ItemBrandView::eventFilter(QObject *watched, QEvent *event)
{
    if(watched == table)
    {
        if(event->type() == QEvent::KeyPress)
        {
            QKeyEvent* keyEvent = (QKeyEvent* ) event;

            if(keyEvent->key() == Qt::Key_Space)
            {
                QModelIndex currentIndex = table->currentIndex();

                int x = table->columnViewportPosition(currentIndex.column());
                int y = table->rowViewportPosition(currentIndex.row());
                int columnWidth = table->columnWidth(currentIndex.column());

                popupMenu->popup(QPoint(table->horizontalHeader()->mapToGlobal(QPoint(x, y)).x(),
                                        table->horizontalHeader()->mapToGlobal(QPoint(x, y)).y()));
                popupMenu->resize(columnWidth, 20);

                return true;
            }
        }

        return false;
    }

    return QWidget::eventFilter(watched, event);
}