>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3260350. --> Reported by: [chi](https://www.drupal.org/user/556138) Related to !90 >>> <p>When the default admin theme has not base_theme defined (like Claro) the following error is thrown:</p> <pre>Warning: Undefined property: Drupal\Core\Extension\Extension::$base_themes in _gin_is_active() (line 873 of themes/contrib/gin/gin.theme).<br>_gin_is_active() (Line: 107)</pre> > Related issue: [Issue #3157134](https://www.drupal.org/node/3157134)