[Toadling]

You can display the View Bar (Command-Shift-V or use the toolbar button) and choose the second pulldown menu from the left in the content area (third from the left if you count the single menu in the sidebar as well). In that menu, you'll find the option to sort projects by due date.

Note that in Planning Mode, all sorting is done at the Project level rather than at the Action level. In Context Mode, sorting is done at the Action level.

Hope this helps.