This is the most relevant question I can find. The feature I am trying to implement is to mimic operation-system dragging behavior on browser. That is when you are dragging a file and then pressing/releasing ctrlKey changes the icon on the pointer, which represents two different operations either copy or move. However, if you enter dragging state and then hold the mouse not making it move, at the point pressing/releasing ctrlkey will not change ctrlKey to true/false unless you move the mouse again.
Check on the console log from this demo: http://jsfiddle.net/YF6UG/4/
According to the post Detecting keydown/up events during HTML5 native drag, I cannot intercept keydown/keypress event while dragging is performed. Is there other way to detect keyboard key press directly instead of tracking ctrlKey from event itself?