How to add a QComboBox in QVTKOpenGLNativeWidget?

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1

Now, I need to add a QComboBox in QVTKOpenGLNativeWidget. However, I fand the signal-slot do not work.

The code is:

#include <qapplication.h>
#include <qsurfaceformat.h>
#include <QVTKOpenGLNativeWidget.h>
#include <qcombobox.h>
#include "qboxlayout.h"
class VTKTestWidget :public QVTKOpenGLNativeWidget
{
public:
	VTKTestWidget()
	{
		m_combobox_ = new QComboBox;
		m_combobox_->addItem("item1");
		m_combobox_->addItem("item2");
		QHBoxLayout* layout = new QHBoxLayout;
		layout->addWidget(m_combobox_);
		this->setLayout(layout);
		connect(m_combobox_, SIGNAL(currentIndexChanged), this, SLOT(widgetComboboxIndexChangeSlot));
	}

public slots:
	void widgetComboboxIndexChangeSlot(int index)
	{
		std::cout << index << std::endl;
	}
protected:
	QComboBox* m_combobox_;
};

int main(int argc, char* argv[])
{
	QSurfaceFormat::setDefaultFormat(QVTKOpenGLNativeWidget::defaultFormat());
	QApplication a(argc, argv);

	VTKTestWidget* widget = new VTKTestWidget;
	widget->show();

	return a.exec();
}

When I change the index of QComboBox, the widgetComboboxIndexChangeSlot would not be called.

How can I fix this problem? Or the QVTKOpenGLNativeWidget can not be treated as a normal QWidget?

Any suggestion is appreciated~~~~