How QPushButton menu opens upward?

[ahmetturan]

I set menu for QPushButton

QMenu *menu=new QMenu(ui->pushButton);
menu->addAction("action 1");
menu->addAction("action 2");
ui->pushButton->setMenu(menu);

QMenu *menu=new QMenu(ui->pushButton);
menu->addAction("action 1");
menu->addAction("action 2");
ui->pushButton->setMenu(menu);

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menu opens downward. How it opens upward?