https://bugs.winehq.org/show_bug.cgi?id=37113
--- Comment #7 from graben info@translucide.ca --- I think I was too tired yesterday, after a couple of coffees this morning, I found the fix and its dead simple and was obvious looking back at the bisect result. Just forget my last comment !
In dlls/ole2.c, just changing around line 2408 :
case DRAGDROP_S_DROP: if (*trackerInfo->pdwEffect != DROPEFFECT_NONE) trackerInfo->returnValue = IDropTarget_Drop(trackerInfo->curDragTarget,...
TO :
case DRAGDROP_S_DROP: if (*trackerInfo->pdwEffect != DROPEFFECT_NONE) IDropTarget_Drop(trackerInfo->curDragTarget,...
In short, not assigning IDropTarget return value to trackerInfo->returnValue does fix the bug for me.
It might however cause a new one for someone other situations, that returnValue must have been added for a good reason, thought it creates a new bug in Illustrator CS6.