When pages are created, the author can choose the 'rank' which defines the order of tabs for users. (The default is 100.)

However, users have the ability to view tabs in this manner or reorder for their viewing pleasure. These options are located within the menu 'Options - Change Page Order' (a section of this page is available below). Simply check the 'Use page rank' button to use the author's designated ordering.

Reference: http://support.sas.com/documentation/cdl/en/idp/60049/HTML/default/p19l33qvtyfa3bn15x4h0m2oq5qg.htm