Add Buttoms To View Text And HTML

To add toolbar buttons for 'View Text Only' and 'View HTML' in the email window, open the 'toolbar.ini' file located in the Opera directory and look for the '[Mail Standard Toolbar]' section then add these lines to the bottom of it:

ButtonX, "Text"="Set mail display type, 0, , , "View""
ButtonX, "HTML"="Set mail display type, 1, , , "View""

Change the 'X' to the next available number from where you added the lines.