title: Mapbox studio : how to display building at any zoom level
body: <p>I'm using mapbox studio to customize a map and I haven't found the way to display building-outline layer at any zoom level.</p>
  <p>If I'm under of 16 zoom level, this layer disappears... even if I force opacity to 1.</p>
  <p>Any idea ?</p>
  <p>Thank you in advance</p>