When I add a new item/attachment to my library, if I right click an old item/attachment before the new one appears, when the new one does appear it steals the selection focus and the right click menu that was opened from the old item now effects the new item.

So for example if I add a new item, right click an old item and click delete, if the new item has appeared in the background before I click delete, the the new item is deleted instead of the old item.