It's an Outlook view setting that needs to change, so do this;
You can change the view of an IMAP folder so that items marked for deletion do not appear. On theView menu, point to Current View, and then click Hide Messages Marked for Deletion. If you are using the Reading Pane, you must turn it back on after using this command. On the View menu, point to Reading Pane, and then click Right or Bottom.