Subject says it all, no? The long version is: when you have several magic items stacked (arrows + 1, potions of strength, of healing), and you Ctrl+click on them to separate one of them (to give it to another party member for example), the separate item is no longer identified and must be identified again to use it. Now, what did this potion do again? This was still the case as of version 0.4.21.
Something related that would be also nice to fix: when we find 10 bolts + 1, could they all be stacked together, so that they can all be identified together? Otherwise put at least a bolt + 2 among them, to make the suspense worthwhile ;-)