There are several lists in the 3x management interface, which may contain several hundred or even thousands items. Unfortunately the list view only shows 100 on one page and there is no way to select all at once (or items distributed over several pages). At the moment you have to repeat your action for each page of 100 items. This happens for example when you mass edit extensions, or you mass re-provision your phones or you delete your old company directory. It would be nice if you had the option to "show all" and an additional "select all" would be convenient, too. So you don't have to scroll a very long list holding Strg. If a "show all items" is not possible, an option to show more, like 1000 would help, too.