To the left of the page buttons in the default old notebook style setting is the status line, which enables the application to provide information to the user about the page currently displayed. The notebook does not supply any default text for the status line.
The application is responsible for associating a text string with the status line of each page on which a text string is to be displayed. The status line can be used in addition to the major and minor tabs to provide the user with additional information on a particular page in the notebook. It is commonly used in large notebooks to assist the user in navigating, by indicating that this page is page 1 of n.
The status text is drawn left-justified by default, but it can be drawn centered or right-justified. The same status text justification applies to all pages in the notebook. This setting is specified by the BKS_STATUSTEXTLEFT style bit. The location of the back pages intersection and the major tabs has no effect on the specification of the status line position. This style bit can be set for the entire notebook.