@NataliyaLys -- Thanks for sharing this feedback. That space is there by design so that when the tour locks into place the first row of thumbnails doesn't start disappearing immediately.
We have received other comments from the community about this space and have discussed making changes to how this looks/works. Could you share a little more about why you'd like to remove that space and what experience you'd expect so we can share that with our designers?
Owen Evans
Lead Product Engineer | StoryMaps