multiple QOpenGLWidgets in the same window only show one and the other can't paint after set QSurfaceFormat::setDefaultFormat

[Princein]

I developed a cross-platform app which can work both mac and windows using qt framework, there are two QOpenGLWidgets in my project, and I need to change the QSurfaceFormat::defaultFormat using QSurfaceFormat::setDefaultFormat() method, here is the code for change QSurfaceFormat::defaultFormat in the main.cpp

int main(int argc, char *argv[])
{
   QSurfaceFormat defaultFormat = QSurfaceFormat::defaultFormat();
//_defaultFormat = defaultFormat;
QSurfaceFormat format;
	format.setSamples(8);
	format.setVersion(3, 3);
#if __APPLE__
	format.setProfile(QSurfaceFormat::CoreProfile);
#elif _WIN32
	format.setProfile(QSurfaceFormat::CompatibilityProfile);
#endif
	//setFormat(format);
	QSurfaceFormat::setDefaultFormat(format);
	QApplication a(argc, argv);
        return a.exec();
}

now, when I run the app, only one QOpenGLWidget can paint normal, the others can't paint anything, even I use a simple code to paint a simple rectangle, it can't paint too, here is the test code in the test .cpp file in my project to paint a simple rectangle :
myopenglview.cpp

#include "myopenglview.h"
MyOpenGLView::MyOpenGLView(QWidget *parent) : QOpenGLWidget(parent)
{
	
}
void MyOpenGLView::initializeGL(){
     	glClearColor(0.0,0.0,0.0,0.0);
	/*
	 * initialize viewing values
	 */
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(0.0,1.0,0.0,1.0,-1.0,1.0);


}

void MyOpenGLView::paintGL(){
   	glClear(GL_COLOR_BUFFER_BIT);
	/*
	 * draw white polyon (rectangle) with corners at
	 * (0.25,0.25,0.0) and (0.75,0.75,0.0)

	 */
	glColor3f(1.0,1.0,1.0);
	glBegin(GL_POLYGON);
	glVertex3f(0.25,0.25,0.0);
	glVertex3f(0.75,0.25,0.0);
	glVertex3f(0.75,0.75,0.0);
	glVertex3f(0.25,0.75,0.0);
	glEnd();

	/*
	 * don't wait!
	 * start processing buffered OpenGL routines
	 */
	glFlush();

}
void MyOpenGLView::resizeGL(int w,int h){

}

when I run the app, I can only see the black background of MyOpenGLView, It seems the MyOpenGLView can only paint the black background correct, the content can't paint, I don't why, can you give me some tips, thanks a lot!