title: IdentityServer4: SSO across different browsers
body: <p>I am implementing back-channel logout in IdentityServer4 by specifying the BackChannelLogoutURL.
  I have two MVC clients (Razor pages) and if I open both clients in the same browser, SSO works great (i.e. if I logout from client1, back channel for client2 got called by IdentityServer4.</p>
  
  <p>However, the back-channel logout URL doesn't get called if I open the two clients in different browsers. I think this because there are different sessions (Please correct me if I am wrong). Can we initiate logout callback per user regardless of the session?</p>