Hide Drupal8 Administer Menu bar on CiviCRM pages
Currently on Drupal8-Civi instance, when you visit any CiviCRM page you will find a Drupal8 Admin menu bar behind the CiviCRM menu bar:
Proposal
It won't be a good idea to expand the CiviCRM menu bar to the width of Drupal8 menu bar, instead hide the Drupal8 menu bar when we are on Civi page. To restore the Drupal8 menu, you can use the existing CiviCRM actions to toggle CiviCRM menu on any Civi page.