Comment 12 for bug 764424

I think the intention was to drag stuff between apps. This can be achieved in several ways. Dropping a file into a launcher icon is too implicit as the user doesn't know the exact destination. For example, when several nautilus instances exist or the destination can be fine grained within the destination app.
When dragging stuff to a launcher icon in the side bar, I think a solution to the bug should be to open the application and let the choose where exactly to drop the file/icon/text/etc. If several instances of the same app exist, pop a preview and let the user hover on the target destination instance to choose it.

The behavior of popping the drop destination existed in an older Ubuntu version but got surprisingly dropped.