Only enable legend title click by default when there are multiple legends

Author: alexshoe

src/components/legend/attributes.js

@@ -179,25 +179,25 @@ module.exports = {
     titleclick: {
         valType: 'enumerated',
         values: ['toggle', 'toggleothers', false],
-        dflt: 'toggle',
         editType: 'legend',
         description: [
             'Determines the behavior on legend title click.',
             '*toggle* toggles the visibility of all items in the legend.',
             '*toggleothers* toggles the visibility of all other legends.',
-            '*false* disables legend title click interactions.'
+            '*false* disables legend title click interactions.',
+            'Defaults to *toggle* when there are multiple legends, *false* otherwise.'
         ].join(' ')
     },
     titledoubleclick: {
         valType: 'enumerated',
         values: ['toggle', 'toggleothers', false],
-        dflt: 'toggleothers',
         editType: 'legend',
         description: [
             'Determines the behavior on legend title double-click.',
             '*toggle* toggles the visibility of all items in the legend.',
             '*toggleothers* toggles the visibility of all other legends.',
-            '*false* disables legend title double-click interactions.'
+            '*false* disables legend title double-click interactions.',
+            'Defaults to *toggleothers* when there are multiple legends, *false* otherwise.'
         ].join(' ')
     },
     x: {

src/components/legend/defaults.js

@@ -9,7 +9,7 @@ var attributes = require('./attributes');
 var basePlotLayoutAttributes = require('../../plots/layout_attributes');
 var helpers = require('./helpers');
 
-function groupDefaults(legendId, layoutIn, layoutOut, fullData) {
+function groupDefaults(legendId, layoutIn, layoutOut, fullData, legendCount) {
     var containerIn = layoutIn[legendId] || {};
     var containerOut = Template.newContainer(layoutOut, legendId);
 
@@ -239,8 +239,9 @@ function groupDefaults(legendId, layoutIn, layoutOut, fullData) {
 
         Lib.coerceFont(coerce, 'title.font', dfltTitleFont);
 
-        coerce('titleclick');
-        coerce('titledoubleclick');
+        var hasMultipleLegends = legendCount > 1;
+        coerce('titleclick', hasMultipleLegends ? 'toggle' : false);
+        coerce('titledoubleclick', hasMultipleLegends ? 'toggleothers' : false);
     }
 }
 
@@ -280,7 +281,7 @@ module.exports = function legendDefaults(layoutIn, layoutOut, fullData) {
     for(i = 0; i < legends.length; i++) {
         var legendId = legends[i];
 
-        groupDefaults(legendId, layoutIn, layoutOut, allLegendsData);
+        groupDefaults(legendId, layoutIn, layoutOut, allLegendsData, legends.length);
 
         if(layoutOut[legendId]) {
             layoutOut[legendId]._id = legendId;