update selected section on children count change
update selected section on children count change

NeoAdonis/osu,smoogipooo/osu,NeoAdonis/osu,smoogipoo/osu,peppy/osu,ppy/osu,NeoAdonis/osu,ppy/osu,smoogipoo/osu,peppy/osu,smoogipoo/osu,peppy/osu,ppy/osu,peppy/osu-new