This test requires two-display configuration, where
- 1st display is operating in HiDPI mode
- 2nd display is non-HiDPI.
In other cases please simply push "Pass".
To run test please push "Start".
Then drag parent / child to different displays and check
that the proper image is shown for every window
(must be "1x" for non-HiDPI and "2x" for HiDPI).
Please try to drag both parent and child,
do it fast several times and check if no artefacts occur.
For Mac OS X please check also the behavior for
translucent windows appearing on the 2nd (non-active) display.
Close the windows.
In case if no issues occur please push "Pass", otherwise "Fail".