[QOpenGLWidget] image overshadows main windows

[debian]

Hello!
I use qt-5.5.1 on Linux x64.
In application main window I add QOpenGLWidget and inherit from it to subclass.
Follow subclass code:
GLWidget::GLWidget(QWidget *parent) :
QOpenGLWidget(parent)
{}
GLWidget::~GLWidget()
{
glDeleteTextures(CHANNEL_MAX, _texture);
}
void GLWidget::add(QImage image, quint8 pos)
{
if (pos < CHANNEL_MAX) {
qDebug() << func << "add position" << pos;
glActiveTexture(GL_TEXTURE0 + pos);
glBindTexture(GL_TEXTURE_2D, _texture[pos]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, image.width(), image.height(),
0, GL_RGB, GL_UNSIGNED_BYTE, image.constBits());
update();
}
}
void GLWidget::initializeGL()
{
initializeOpenGLFunctions();
glClearColor(0, 0, 0, 1);
glEnable(GL_TEXTURE_2D);
glGenTextures(CHANNEL_MAX, _texture);
}
void GLWidget::paintGL()
{
qDebug() << func;
glDrawArrays(GL_TEXTURE_2D_ARRAY, _texture[0], CHANNEL_MAX);
}
void GLWidget::resizeGL(int w, int h)
{}

All work, but I have several problems:

• image overshadows mainwindows
• I always see only one image, but I wait several images to one line

How can I solve this problem?
Thank you and excuse my bad english.