Add tooltip ungrouping for multiple X. Fix #628.

c3.js

@@ -2281,15 +2281,23 @@
                 selectedData = sameXData.map(function (d) {
                     return $$.addName(d);
                 });
+
+                if (config.tooltip_grouped) {
                     $$.showTooltip(selectedData, mouse);
+                }
+                else {
+                    $$.showTooltip([closest], mouse);
+                }
 
                 // expand points
                 if (config.point_focus_expand_enabled) {
                     $$.expandCircles(closest.index, closest.id, true);
                 }
 
+                if (config.tooltip_grouped) {
                     // Show xgrid focus line
                     $$.showXGridFocus(selectedData);
+                }
 
                 // Show cursor as pointer if point is close to mouse position
                 if ($$.dist(closest, mouse) < 100) {

src/interaction.js

@@ -271,15 +271,23 @@ c3_chart_internal_fn.generateEventRectsForMultipleXs = function (eventRectEnter)
             selectedData = sameXData.map(function (d) {
                 return $$.addName(d);
             });
+
+            if (config.tooltip_grouped) {
                 $$.showTooltip(selectedData, mouse);
+            }
+            else {
+                $$.showTooltip([closest], mouse);
+            }
 
             // expand points
             if (config.point_focus_expand_enabled) {
                 $$.expandCircles(closest.index, closest.id, true);
             }
 
+            if (config.tooltip_grouped) {
                 // Show xgrid focus line
                 $$.showXGridFocus(selectedData);
+            }
 
             // Show cursor as pointer if point is close to mouse position
             if ($$.dist(closest, mouse) < 100) {