After having been able to select entire columns of emails for deletion, or to move between folders, suddenly Outlook has limited me to no more than 20 items. If I try to select more than that, it collapses to one item, and similarly, if I try to add more than that, using the ctrl key, it collapses to one item. I can't find any preference or option to affect this, and can't find any reference to it online. Did I accidentally reset something?