How to add two CSS classes with ckeditor 5?

TYPO3 Questions Backend (UI / Configuration / Permissions)
1

we have instances where the editor should be able to style tables according to bootstrap.

this requires the classes ‘table’ and ‘table-striped’ at the same time.
all my configuration results in the end only in one class.
The strange thing:

  1. setting the style adds both classes and after storing the CE all is fine.
  2. if this CEs is edited again the ‘table’ class is gone and therefore all styling

why is the class removed? how can I avoid it?

what configuration is required for a stable setting?

there is no example for the yaml file configuration with multiple classes.
I tried multiple ways, which seem equivalent:

editor:
  config:
    toolbar:
    style:
      definitions:
        - { name: "1 gestreifte Tabelle", element: "table", classes: [ 'table table-striped'] }
        - { name: "2 gestreifte Tabelle1", element: "table", classes: [ 'table', 'table-striped'] }

in the special CSS file I defined it with and without table tag.

table.table.table-striped { }
.table.table-striped {  }

I also tried defining the class table on it’s own. but it is always removed when the editor is loaded. Even after an explicit storing while editing: though a further editing and storing removes the table class.

As my CSS-file only declares the classes and does not repeat the whole definition from bootstrap the editor does not see the complete styling in the edit field - and especially does not see the missing class.