Thank you Alexander_I for your forum post back in 2006! I don’t know who you are, but you gave me the critical clue I needed to solve a bug I’ve been puzzling over for two weeks. (the same window was accidentally registered with two different drag&drop APIs — I was unaware of the older WS_EX_ACCEPTFILES/WM_DROPFILES API)
http://msdn.microsoft.com/en-us/library/windows/desktop/bb776406(v=vs.85).aspx