           offsets[d.get 'sector'] += d.val() / d.sector.total_value() * @height
           old
         ).
-        attr("title", (d) -> d.tooltip_text())
+        attr("data-tooltip", (d) -> d.tooltip_text())
 
 class D3.mekko.GroupCollection extends Backbone.Collection
   model: D3.mekko.NodeGroup

    draw: =>
      @prepare_data()
      margins =
        top: 40
        bottom: 100
        left: 30
        right: 30

      @width = (@container_node().width()   || 490) - (margins.left + margins.right)
      @height = (@container_node().height() || 402) - (margins.top + margins.bottom)

        data(@sector_list.models, (d) -> d.get 'key' ).
        transition().duration(500).
        attr("dy", (d) => @x(d.total_value() / 2) + 5 ).
        text((d) -> "#{d.get 'key'} #{parseInt d.total_value()} PJ")

      # we need to track the offset for every sector
      offsets = {}
