Journal.Email items show as HTML if system-sent but are shown in plain text if created by the email listener.
Any notification sent through Rules or Workflows when added as a Journal.Email item are being stored as HTML allowing the toolbar to be used to amend the Forwards and Replies.
If the Listener creates the Journal.Email record, the body of the email is just "text" and when forwarded or replied there are no options for the HTML Toolbar.
1. Login to the Application as Admin role and select Configure Application.
2. Expand Email Configuration and select Servers.
3. Under the Incoming message handling general rules, change the option of Store Journal Email As from Text to HTML.
4. Save these changes and refresh the application.