QPointer and double deletion

[mtrpoland]

I have a

QList<QPointer<MTR::RowBox> > rowBoxes;

QList<QPointer<MTR::RowBox> > rowBoxes;

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that is a private member of my main widget.
I want to store pointers to a few widgets in this list as well as I want to place these widgets in a gridLayout. My concern is connected to possible double deletion of these widgets as first may be done by a parent widget (received by layout) and second may be done by QList.

I receive SIGSEV for this code:

QGridLayout *qgl = new QGridLayout();
	pawnBox = new MTR::PawnBox();
 
	QPointer<MTR::RowBox> rbOne = new MTR::RowBox();
	rowBoxes.push_back(rbOne);
	QPointer<MTR::RowBox> rb2 = new MTR::RowBox();
	rowBoxes.push_back(rb2);
	QPointer<MTR::RowBox> rb3 = new MTR::RowBox();
	rowBoxes.push_back(rb3);
 
	QWidget *w1 = new QWidget();
	w1->setFixedSize(50,50);
	qgl->addWidget(w1,0,0,1,2);
	qgl->addWidget(rbOne,1,0);
	qgl->addWidget(pawnBox,1,1,3,1);
	qgl->addWidget(rb2,2,0);
	qgl->addWidget(rb3,3,0);
	gameScreen->setLayout(qgl);

QGridLayout *qgl = new QGridLayout();
	pawnBox = new MTR::PawnBox();
	
	QPointer<MTR::RowBox> rbOne = new MTR::RowBox();
	rowBoxes.push_back(rbOne);
	QPointer<MTR::RowBox> rb2 = new MTR::RowBox();
	rowBoxes.push_back(rb2);
	QPointer<MTR::RowBox> rb3 = new MTR::RowBox();
	rowBoxes.push_back(rb3);
	
	QWidget *w1 = new QWidget();
	w1->setFixedSize(50,50);
	qgl->addWidget(w1,0,0,1,2);
	qgl->addWidget(rbOne,1,0);
	qgl->addWidget(pawnBox,1,1,3,1);
	qgl->addWidget(rb2,2,0);
	qgl->addWidget(rb3,3,0);
	gameScreen->setLayout(qgl);

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where MTR::RowBox is a pure subclass of a QWidget.

Backtrace is obvious:

#0  0x080559d6 in QList<QPointer<MTR::RowBox> >::~QList ()
#1  0x08052eb7 in MyWidget::~MyWidget ()
#2  0x0804e89e in main ()

#0  0x080559d6 in QList<QPointer<MTR::RowBox> >::~QList ()
#1  0x08052eb7 in MyWidget::~MyWidget ()
#2  0x0804e89e in main ()

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A quotation from QPointer class documentation:

Guarded pointers are useful whenever you need to store a pointer to a QObject that is owned by someone else, and therefore might be destroyed while you still hold a reference to it.