Indicates if sidebar is in the flat mode. If sidebar is in the flat more, only node icon will be displayed. Parent child structures are also ignored. Flat mode is useful to make sidebar take less space. You can define it during object creation: let sidebar = new w2sidebar({ name : 'sidebar', flat : true, nodes: [ { id: 'id-1', text: 'Level 1' }, { id: 'id-2', text: 'Level 2' }, { id: 'id-3', text: 'Level 3' } ] }); or during run-time: w2ui.sidebar.flat = true; w2ui.sidebar.refresh();