I'm not sure I understand what you mean by "in the top right". Top right of what window?
When I'm in "mail", I don't have that option.
I'm still having trouble finding the button you are talking about...
on your mac, when u send an email to yourself, let its say (Holidays in united states). hover your mouse over that blue bubble containing that text until you see the drop down menu. choose "Remove from previous recipients list" should be gone!!