How can I control the tabs that appear in the TabList dropdown?

I have a tab that appears as the right most tab. It has a plus sign on it and is used to create new tabs. When the user clicks the '(+)NewTab' a new tab is created just to the left of the '(+)NewTab' and defaults to my 'Search' screen.

However I do not want to display the '(+)NewTab' in the list when the user clicks the TabList button.

Thanks