Back button after opening an article in the case activity stream does not navigate back to the csm/csp portalDescriptionClicking an article link from the case activity stream when in csm/csp portal opens the article in platform view in the same case window. Clicking on the back button from there does not take back to the case form.Steps to Reproduce 1. Login as administrator.2. Create a new case and attach articles to it. Check that the articles attached are displayed in the activity stream.3. Login as a non-admin user.4. Navigate to the case created above. Click on the article link present in the activity stream. Check that, the article is navigating to platform view of the article in the same window.5. Click on the browser back button and observe the behavior.WorkaroundThis is a known limitation and expected behavior for the current platform design. Once navigated out of the Service Portal, the back button can not bring the Portal page back. The following workarounds can be adopted:- Change the kb_view page to Portal kb page in the article link, so to avoid users to navigate out of the portal to view an article: Modify the Knowledge Article Link that is populated when we click on Attach button from Contextual Search Results - Attach the document into the work notes instead of linking to it. This is an existing configuration under Contextual Search > Table Configuration > Search Action Configuration > Change the attachment type field of Attach action to 'Embed Article'. This should be done with caution, only articles that can be shown to a public or wider audience should be embedded. Administrators should make sure that access and intended audience of the article being attached is set correctly through appropriate ACLs/User Criteria.Related Problem: PRB1287147