You should have removed the left column to make the slider full-width

I did that, but thought that I was doing it wrong, because then the categories menu was overlapping.

The categories can be open by default as it was configured initially or open by click.

Correct, but on your demo https://woodmart.xtemos.com/ it has an open categories menu and it doesn’t overlap the slider. That is exactly what I want. So how to have open categories menu without it overlapping the slider?