The iManage Work panel appears/is visible only when one email is selected. Due to Microsoft Outlook limitations, multi-select is not supported. If you select more than one email, the panel closes even when it is pinned and reappears when only one email is selected. 

To access the panel in Microsoft Outlook, select an email and then select See more items  > iManage Work. Sign in to your Microsoft Exchange account and then your iManage Work account to display the email management options in the iManage Work panel and start using them. The panel can also be accessed while composing emails, replying to and forwarding emails, creating a new event, and viewing an event (only Save attachments is available here)

After this first-time procedure, you can use the See more items  > iManage Work to open the panel. Once in a while if your authentication token expires, you may need to sign in to your iManage Work account using the Sign in button in the panel.

You can add the iManage Work option to the Outlook toolbar to access it quickly and pin it to ensure it persists and does not disappear when you select another email.