REQ_117.4: An LMS shall provide a disabled navigation UI device corresponding to a PreviousNavigation event when:• The Current A

An LMS shall provide a disabled navigation UI device corresponding to a PreviousNavigation event when:• The Current Activity is a child of a (Sequencing Control Mode) Flow equalsFalse cluster.• The Current Activity is a child of a (Sequencing Control Mode) Forward Onlyequals True cluster.• If traversing Backward from the Current Activity encounters a cluster activitywith (Sequencing Control) Flow equal to False.• If traversing Backward from the Current Activity encounters a cluster activitywith (Sequencing Control) Forward Only equal to False.• If traversing Backward from the Current Activity will result in walking off theroot of the Activity Tree.