Outlook Deleted entire inbox while typing new email

I actually work in IT for a company and a user called me to advise her entire outlook inbox was deleted while she was typing a new email. I watched her session to see exactly when it happened and it happened as she typed "T" in the word "today". I just wanted to know why this happened. I googled the issue as well as keyboard commands in Outlook and I can't see to find an answer. She's going to manually move the emails she wants back over but I don't want this to happen to her again. Any ideas?