we recently stumbled to this same problem. We noticed that as you scroll down to view the list of objects in your shared objects pane the distance between the cursor and the item being dragged also increases. Thus if you drag an object from the bottom of the list, the object you are trying to paste will not be in the area you are pasting to. As a temporary solution we sorted the shared objects via owner and collapsed each node opening only the node which contain the shared object we want to drag. It would also help to use the zoom out function in order to increase the drop area for your shared object.
hope this help.