The Project Number, Account Number, and Task fields require some additional setup.
Project Number - The numbers in this list must be added individually to the Desktop in the Work > Work Flow Setup > Account Project Number module.
Enable the Force Use of Predefined Account Project Numbers option in the Work Options.
Account Number - The numbers in this list must be added individually to the Desktop in the Work > Work Flow Setup > Account Number module.
Enable the Force Use of Predefined Account Numbers option in the Work Options.
Task - The tasks in this list come from the Desktop in the Work > Work Flow Setup > Work Tasks module. They only appear in the list if the Timesheet Enabled checkbox is checked on the task record.