I still haven't reproduce this blinking problem yet.
It appears to be unrelated to the drag/drop issue with the SetPoint driver. The drag/drop problem is very odd and may be a Windows OS bug having something to do with using SetWindowHookEx(qJournalRecordProc,...). I'm guessing both the SetPoint driver and Qt use this which should theoretically be OK but it's not. Qt ONLY uses this hook while the mouse is grabbed (captured). In this screen blink case, the mouse isn't captured. Like I said, it's an unrelated problem.