What does the All Values Required field, in the Definition Workflow Details table on the Item Management tab of the Edit Item Class task mean?

When checked, all attributes of the associated entity specified on that row must be populated by the assignee in order to for the workflow to proceed to the next step of the definition workflow.

For example, if the associated entity is Physical Attributes, then all attributes in the attribute group must be populated by the assignee in the New Item Request workflow step.