|Available in: Group, Professional, Enterprise, Performance, Unlimited, and Developer Editions|
To force case assignment rules, select Default under Case Assignment Checkbox. This option prevents end-users from turning off case assignment when editing or creating a case. To allow end-users to turn on or off case assignment rules, select Show on edit page under Case Assignment Checkbox. If you select both options, the assignment checkbox is displayed and is checked by default. The Default setting forces the assignment rule to run, unless you also display the checkbox and a user manually deselects the checkbox.
To update the case assignment checkbox, edit the Layout Properties of the case page layout.