Recently I faced an issue when Overview tab was missing in Workflow history for a customised role.
Initially I thought it might be the permission issue though the corresponding menu item has full access for the given role.
On digging more, I found few controls on the workflow form are available only for Admin users.
Below highlighted statement in the class “WorkflowStatusForm” defines “Overview” tab to be available only for admin users.
Error text is not displayed for non-admin users due to condition in the below code snippet in the same class