Unread emails

There has been a recent change in the treatment of unread emails when using webmail.  If I delete an email, my cursor falls to the next email and marks it read.  If I don't want it marked read, I have to quickly change it.  If I am not quick enough it drops to the list of read emails and I most likely miss reading it.  It used to be that if I was on the unread sort that emails did not change to read unless I made the change.  How can I go back to that?