* add multiTooltipTitleTemplate option.

src/js/Chart.Core.js

@@ -197,6 +197,9 @@
             // String - Template string for single tooltips
             multiTooltipTemplate: "<%if (datasetLabel){%><%=datasetLabel%>: <%}%><%= value %>",
 
+            // String - Template string for multiple tooltip title
+            multiTooltipTitleTemplate: '<%= label %>',
+
             // String - Colour behind the legend colour block
             multiTooltipKeyBackground: '#fff',
 
@@ -1046,7 +1049,7 @@
                         labels: tooltipLabels,
                         legendColors: tooltipColors,
                         legendColorBackground: this.options.multiTooltipKeyBackground,
-                        title: ChartElements[0].label,
+                        title: template(this.options.multiTooltipTitleTemplate, ChartElements[0]),
                         chart: this.chart,
                         ctx: this.chart.ctx,
                         custom: this.options.customTooltips