the #GtkWidget to use as the contents of the page
the #GtkWidget to be used as the label for the page, or null to use the default label, “page N”
the widget to use as a label for the page-switch menu, if that is enabled. If null, and tab_label is a #GtkLabel or null, then the menu label will be a newly created label with the same text as tab_label; if tab_label is not a #GtkLabel, menu_label must be specified if the page-switch menu is to be used.
the index (starting from 0) of the appended page in the notebook, or -1 if function fails
Appends a page to notebook, specifying the widget to use as the label in the popup menu.