     @widen_chart((@width - @x_offset) + 100) if @column_band.rangeBand() < @minimum_column_width
 
   render_series_1: ->
-    @series_1 = @svg.selectAll('.series1').data(@_data)
+    @series_1 = @svg.selectAll('.series1').data(@_data, (d) -> d.key)
     @series_1.enter().append('g').attr('class', 'series1')
     @series_1.attr('transform', (d,i) => "translate(#{@series_1_x[i]}, 0)")
     @series_1.exit().remove()

      .attr('height', @height)
      .style('stroke', 'none')
      .style('fill', 'none')
    #

    @set_legend_x()

  set_legend_x: ->


  initialize_legend: ->
    @legend or= @svg.append('g')
    # TEMP
    @legend.selectAll('rect.test').data([1]).enter()
      .append('rect')
