This Mark menu contains the various page marking commands.
Toggle the marked state of the current page. If the current page is marked, it will become unmarked; if the current page is unmarked, it will be marked. Marked pages will appear in a different font in the page list.
Mark or unmark all of the pages.
Mark the even/odd numbered pages.
Mark the un-marked pages and un-mark the marked pages (i.e. toggle the marked status of each page).