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".