If you create an issue by clicking the big blue "Create" button at the top of the screen, the issue will allow you to add a due date (assuming that your field configuration allows the due date field). However, if you are in the Backlog and you click the "Create Issue" link at the bottom of the backlog list, the resulting issue will not include the option for a due date.
Is there a way to make sure that BOTH methods for creating issues allow access to the Due Date field?