app/assets/javascripts/highcharts/themes/dark-green.js in highcharts-rails-3.0.10 vs app/assets/javascripts/highcharts/themes/dark-green.js in highcharts-rails-4.0.0

@@ -243,10 +243,10 @@
 		trackBorderColor: '#666'
 	},
 
 	// special colors for some of the
 	legendBackgroundColor: 'rgba(0, 0, 0, 0.5)',
-	legendBackgroundColorSolid: 'rgb(35, 35, 70)',
+	background2: 'rgb(35, 35, 70)',
 	dataLabelsColor: '#444',
 	textColor: '#C0C0C0',
 	maskColor: 'rgba(255,255,255,0.3)'
 };