You need to unregister 'register', 'menu:filter:filter' event and register a new event in your custom plugin:

'menu:filter:filter' => [
    'Elgg\Menus\Filter::registerFilterTabs' => ['unregister' => true],
    'MyPlugin\Menus\Filter::registerFilterTabs' => [],
],

Thank you very much for your response.
I was hoping there was a single file ("filter.php", for example) that I could easily copy and modify.

I see the solution isn't as easy as I thought.

Thank you very much, again.

Best regards.