We have implemented an Outlook Add in that uses the SupportsPinning option from Req Set 1.5 and the SupportsSharedFolders option from Req Set 1.8. Both options are working fine in Windows Outlook Native client but malfunction in Outlook.com, outlook.office365.com, OWA (tested in latest Chrome, IE and Edge).
These are the steps and the outcome:
- Open Shared Inbox in web outlook
 - Select email
 - Open Add-in
 - Pin Add-in
 - Select another email
 - OUTCOME: Add-in window closes, EXPECTED: Add-in window remains open
 
The other strange thing is that if you then select another message, the add-in remains closed BUT if you select an email that you previously opened the add-in on, in the shared inbox, the add-in reopens.
Does anyone know why this behaviour is occurring? Is there a way around it??