By design, the Messages Panel will only display the actions and messages that are associated with leads that are assigned directly to you.
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That said, there is a way to view the Messages associated with other Agents on your account-- through the Email Accountability Dashboard.
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To access this information, navigate to the Reporting tab in your left-hand menu bar, and then select the Email Accountability option.
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Once on the Email Accountability dashboard, scroll to the Agent's name that you'd like to view, and then click the Alerts button to expand the selection. This will then display any Messages present in the Agent's account, along with how old the Messages are.
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