I've enabled HDPI by setting QT_SCALE_FACTOR environment variable.
Then I've found that my main window appears somewhere behind the screen.
After some debugging I've found that frameGeometry() returns less than zero.
P.s. : There are 2 monitors in the system also. One has 96 dpi, other is in 144 dpi mode.
For example:
left top = {-1920, -30}
width, height = {968, 820}
Has anyone faced any similar problem?