Limit the number of sign in/out notifications
When several accounts are active, some of them with redundant contacts, the sign in/out notifications for these contacts are displayed (as well as the relevant sound played) several times.
It would be better if these contacts (as grouped for having the same JID within several rosters, but maybe also belonging to a same metacontact in a single roster) were considered as a single one, and the various visual and audio notifications done only once.
For example, sign out notices could be sent only when the last resource of the "group" leaves, and only notice for sign-ons where all the resources for this contact were previously offline (or maybe if the new resource as a higher priority than all the currently connocted ones for that user).