From your favourite (!?) bug hunter.
As you can see, no matter how I modify mail index toolbar in admin settings, toolbar reamain default one.
Which version (from admin/change log and versions)? egroupware-docker (19.1.20190925) hardy; urgency=low
Installation type: package installation
Does the error occur after an update? No, also before last update.
Are there any references in the web server error log?
Which database is used: MySQL
Which web server is used: Apache
Which version of PHP is used? PHP Version 7.3.11-1+ubuntu18.04.1+deb.sury.org+1