title: How does Keycloak determinate a User in new browser window?
body: <p>I try to make sense of following problem:</p>
  <p>There is:</p>
  <ul>
  <li><code>app1.gatekeeper-test.com</code></li>
  <li><code>app2.other-url.com</code></li>
  </ul>
  <p>Those two Clients(app1, app2) are in the same realm (secured behind 2 Gatekeepers)
  Both are pointing to the same ressource server - Cookies are fully-scoped.</p>
  <ol>
  <li>I log in as <code>user1</code> into <code>app1.gatekeeper-test.com</code>.</li>
  <li>I open <code>app2.other-url.com</code> in a new tab it logs me automatically in as <code>user1</code>.</li>
  <li>If I open <code>app1.gatekeeper-test.com</code> in a private window I need to login again.</li>
  <li>There is nothing which is globally scoped and I can't find the reason how keycloak is determining the user.</li>
  </ol>
  <p>How is this possible? There has to be some Frontend-State-Mechanism which lets Keycloak know, that this is <code>user1</code>, which is trying to access app2? I am quite puzzled... (Tested on Chrome 80.0.3987.87)</p>