Problem/Motivation
As part of #3343940: Field UI 2023 User Research, we discovered that users have challenges orienting themselves in the Drupal Admin UI. One of the many causes to this is that Drupal doesn't indicate active menu trail in the Toolbar when user navigates to pages that are deeper in the administrative UI. While this information is available through the breadcrumbs, to make users more confident about their orientation, it is important to communicate the current location using multiple mechanisms as described by this Nielsen Norman article about navigation.
Proposed resolution
Indicate active menu trail even for pages that are not included in Toolbar to help users orient in which section of the site they are currently on.