Some employee time card approver cannot see the details

Hi guys,

I want to assign 2 employees to approve all the employee time cards, meaning that either one of them can approve or reject. So I create a workgroup called “management”, with both employees (A and B) included. And I set employee A as the approver. The setting is basically like this:

Now for Employee A, he can approve or reject all the employee time cards normally. For emplyee B, he should be able to check the employee time cards from “my workgroup’s approvals”. But the problem is, although he could see all the records pending approval, he cannot get into the details by double-clicking each record. So could anyone please tell me what’s wrong? Thanks!