How can I prevent email being marked as read immediately upon display in preview pane.. As i delete an email in the inbox, it goes to next email and it is marked as read immediately.. can i prevent or delay this action.. I am using el Capitan. I do not want to close the preview pane.. I tried the defaults write com.apple.Mail MarkAsReadDelay 5 command also but it does not work as i do not see any effect of this.. searched on the net but could not locate any fix for this..