E_FAIL error in case of drag-and-drop aborting
WinSCP (6.5.3 Build 16364) returns
E_FAIL
error from IDropTarget::Drop
handler when Abort selected from drag-and-drop menu. This error is returned to source app via DoDragDrop
return value. According to docs, target app should return DRAGDROP_S_CANCEL
when drag-and-drop was canceled, therefore IDropTarget::Drop
result should be DRAGDROP_S_CANCEL
.