Ok, so I set a filter for a folder to show only unread items.  (I have done this many times on older versions) scan through the list and click on an email to read it (basically to see if I want to delete right away). However, before I can actually read the email it disappears from the list, like within 3 seconds. It is still in the folder just not in the unread list.  I have to finish what I am doing in the unread list, like delete those that I want to then reset the filter.  It is just annoying.