I run the example "2dpainting" in "C:\Qt\Examples\Qt-5.12.2\opengl\2dpainting". When I set the graphics card (Intel(R) UHD Graphics, it is the graphics card that example is using) is disabled, the example crashed. BUT, at the same time, the Chrome which is playing a youtube's video has not crashed. Then, I found the CPU usage of Chrome has increased a lot. So, I think this is a bug of Qt which can't handle the switching between graphics card and cpu well.

This is a reproducible bug on my environment.

Reporter add: When I run the example "qopenglwidget" in "C:\Qt\Examples\Qt-5.12.2\opengl\qopenglwidget", there was also a crash.

Reporter add: When I implemented QGLWidget by GLWidget, the "2dpainting" example did not crash. Does anyone know why?