[QOpenGLWidget] Output image in manwindow and separated float window

[debian]

Hello!
Now I use QOpenGLWidget subclass for output images in application main window, after user select region of interest I spit main window and output selected area also on QOpenGLWidget subclass.
But user wants view selected area in separated window, I create widget based on QDialod, add my QOpenGLWidget subclass and add images on it, split main window disabled.
Unfortunately I see only white square on float window, selected area output on main window with another images.
Can I use QOpenGLWidget subclass on main window and separated float window at one time?
Thank you and excuse my bad english.