QT Layout problem

[bod]

I want to add a textedit widget to my window. It has a "QHBoxLayout" layout.
I'm tryin to add this textedit but I cannot. I think, it places the textedit under the treewidget.
I don't understand why.
Can u help me pls?
Here is my code:

glWidget = new GLWidget;
	tree = new QTreeWidget;
	tree->setHeaderLabel("Items");
	qtItem = new QTreeWidgetItem(tree);
	qtItem->setText(0, tr("QtLogo"));
                QWidget *tmpw = new QWidget();
	QTextEdit *cmd = new QTextEdit(tmpw);
                QHBoxLayout *mainLayout = new QHBoxLayout;
                mainLayout->addWidget(glWidget);
	mainLayout->addWidget(tree);
	mainLayout->addWidget(tmpw);

glWidget = new GLWidget;
	tree = new QTreeWidget;
	tree->setHeaderLabel("Items");
	qtItem = new QTreeWidgetItem(tree);
	qtItem->setText(0, tr("QtLogo"));
                QWidget *tmpw = new QWidget();
	QTextEdit *cmd = new QTextEdit(tmpw);
                QHBoxLayout *mainLayout = new QHBoxLayout;
                mainLayout->addWidget(glWidget);
	mainLayout->addWidget(tree);
	mainLayout->addWidget(tmpw);

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Edit: I'm sorry I posted it twice mistakely.