CKEditor wrong toolbar is displayed after trying to remove plugin or button

I'm trying to customize the layout of the toolbar.

Step to reproduce:

1. Open any page via editing in CKEditor. By default you'll see this toolbar
2. Navigate to xwiki/bin/admin/XWiki/XWikiPreferences?editor=globaladmin&section=WYSIWYG CKEditor config page
3. Add this code as custom advanced configuration

config.removePlugins = 'source,maximize'

1. Force refresh the open page for editing, and you'll see the entire toolbar and not the default one or updated without buttons

About removePlugins is here
I've checked the documentation and the parameters that remove [buttons](https://ckeditor.com/docs/ckeditor4/latest/api/CKEDITOR_config.html#cfg-removeButtons) from the toolbar, and it's worked for me, however, the entire toolbar is displayed.
'

config.removeButtons = 'Source,Maximize'

Alternative workaround for me, as I did last week. But it requires to list all elements that I'd like to have

config.toolbar_Custom = [
    [ {there list names of elements} ]
];
config.toolbar = 'Custom';

Actual result
The buttons still exist and the entire toolbar is displayed, even plugins and features that are disabled.

Expected result
The buttons are removed. And the toolbar is displaying only enabled elements.