diff --git a/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button-debug.js b/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button-debug.js
index 8e19cb21a61..4379be5e3f2 100644
--- a/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button-debug.js
+++ b/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button-debug.js
@@ -64,7 +64,9 @@ Y.namespace('M.atto_html').Button = Y.Base.create('button', Y.M.editor_atto.Edit
      * @private
      */
     _showHTML: function() {
-        var host = this.get('host');
+        var host = this.get('host'),
+            textareaLabel = host.textareaLabel;
+
         if (!this.get('isHTML')) {
             // Unhighlight icon.
             this.unHighlightButtons('html');
@@ -79,6 +81,11 @@ Y.namespace('M.atto_html').Button = Y.Base.create('button', Y.M.editor_atto.Edit
             host.textarea.hide();
             this.editor.show();
 
+            if (textareaLabel) {
+                // Update the textarea label.
+                textareaLabel.setAttribute('for', this.editor.getAttribute('id'));
+            }
+
             // Focus on the editor.
             host.focus();
 
@@ -109,6 +116,10 @@ Y.namespace('M.atto_html').Button = Y.Base.create('button', Y.M.editor_atto.Edit
             this.editor.hide();
             host.textarea.show();
 
+            if (textareaLabel) {
+                // Update the textarea label.
+                textareaLabel.setAttribute('for', host.textarea.getAttribute('id'));
+            }
 
             // Focus on the textarea.
             host.textarea.focus();
diff --git a/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button-min.js b/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button-min.js
index 0b9d2ea5299..18931efa74d 100644
--- a/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button-min.js
+++ b/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button-min.js
@@ -1 +1 @@
-YUI.add("moodle-atto_html-button",function(e,t){e.namespace("M.atto_html").Button=e.Base.create("button",e.M.editor_atto.EditorPlugin,[],{initializer:function(){this.addButton({icon:"e/source_code",callback:this._toggleHTML})},_toggleHTML:function(){this.set("isHTML",!this.get("isHTML")),this._showHTML()},_showHTML:function(){var e=this.get("host");this.get("isHTML")?(this.highlightButtons("html"),e.disablePlugins(),e.enablePlugins(this.name),e.updateOriginal(),e.textarea.setStyles({width:this.editor.getComputedStyle("width"),height:this.editor.getComputedStyle("height"),margin:this.editor.getComputedStyle("margin"),padding:this.editor.getComputedStyle("padding")}),this.editor.hide(),e.textarea.show(),e.textarea.focus()):(this.unHighlightButtons("html"),e.enablePlugins(),e.updateFromTextArea(),e.textarea.hide(),this.editor.show(),e.focus(),this.markUpdated())}},{ATTRS:{isHTML:{value:!1}}})},"@VERSION@",{requires:["moodle-editor_atto-plugin","event-valuechange"]});
+YUI.add("moodle-atto_html-button",function(e,t){e.namespace("M.atto_html").Button=e.Base.create("button",e.M.editor_atto.EditorPlugin,[],{initializer:function(){this.addButton({icon:"e/source_code",callback:this._toggleHTML})},_toggleHTML:function(){this.set("isHTML",!this.get("isHTML")),this._showHTML()},_showHTML:function(){var e=this.get("host"),t=e.textareaLabel;this.get("isHTML")?(this.highlightButtons("html"),e.disablePlugins(),e.enablePlugins(this.name),e.updateOriginal(),e.textarea.setStyles({width:this.editor.getComputedStyle("width"),height:this.editor.getComputedStyle("height"),margin:this.editor.getComputedStyle("margin"),padding:this.editor.getComputedStyle("padding")}),this.editor.hide(),e.textarea.show(),t&&t.setAttribute("for",e.textarea.getAttribute("id")),e.textarea.focus()):(this.unHighlightButtons("html"),e.enablePlugins(),e.updateFromTextArea(),e.textarea.hide(),this.editor.show(),t&&t.setAttribute("for",this.editor.getAttribute("id")),e.focus(),this.markUpdated())}},{ATTRS:{isHTML:{value:!1}}})},"@VERSION@",{requires:["moodle-editor_atto-plugin","event-valuechange"]});
diff --git a/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button.js b/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button.js
index 8e19cb21a61..4379be5e3f2 100644
--- a/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button.js
+++ b/lib/editor/atto/plugins/html/yui/build/moodle-atto_html-button/moodle-atto_html-button.js
@@ -64,7 +64,9 @@ Y.namespace('M.atto_html').Button = Y.Base.create('button', Y.M.editor_atto.Edit
      * @private
      */
     _showHTML: function() {
-        var host = this.get('host');
+        var host = this.get('host'),
+            textareaLabel = host.textareaLabel;
+
         if (!this.get('isHTML')) {
             // Unhighlight icon.
             this.unHighlightButtons('html');
@@ -79,6 +81,11 @@ Y.namespace('M.atto_html').Button = Y.Base.create('button', Y.M.editor_atto.Edit
             host.textarea.hide();
             this.editor.show();
 
+            if (textareaLabel) {
+                // Update the textarea label.
+                textareaLabel.setAttribute('for', this.editor.getAttribute('id'));
+            }
+
             // Focus on the editor.
             host.focus();
 
@@ -109,6 +116,10 @@ Y.namespace('M.atto_html').Button = Y.Base.create('button', Y.M.editor_atto.Edit
             this.editor.hide();
             host.textarea.show();
 
+            if (textareaLabel) {
+                // Update the textarea label.
+                textareaLabel.setAttribute('for', host.textarea.getAttribute('id'));
+            }
 
             // Focus on the textarea.
             host.textarea.focus();
diff --git a/lib/editor/atto/plugins/html/yui/src/button/js/button.js b/lib/editor/atto/plugins/html/yui/src/button/js/button.js
index 9c65d866ad0..12f1e6ab720 100644
--- a/lib/editor/atto/plugins/html/yui/src/button/js/button.js
+++ b/lib/editor/atto/plugins/html/yui/src/button/js/button.js
@@ -62,7 +62,9 @@ Y.namespace('M.atto_html').Button = Y.Base.create('button', Y.M.editor_atto.Edit
      * @private
      */
     _showHTML: function() {
-        var host = this.get('host');
+        var host = this.get('host'),
+            textareaLabel = host.textareaLabel;
+
         if (!this.get('isHTML')) {
             // Unhighlight icon.
             this.unHighlightButtons('html');
@@ -77,6 +79,11 @@ Y.namespace('M.atto_html').Button = Y.Base.create('button', Y.M.editor_atto.Edit
             host.textarea.hide();
             this.editor.show();
 
+            if (textareaLabel) {
+                // Update the textarea label.
+                textareaLabel.setAttribute('for', this.editor.getAttribute('id'));
+            }
+
             // Focus on the editor.
             host.focus();
 
@@ -107,6 +114,10 @@ Y.namespace('M.atto_html').Button = Y.Base.create('button', Y.M.editor_atto.Edit
             this.editor.hide();
             host.textarea.show();
 
+            if (textareaLabel) {
+                // Update the textarea label.
+                textareaLabel.setAttribute('for', host.textarea.getAttribute('id'));
+            }
 
             // Focus on the textarea.
             host.textarea.focus();
diff --git a/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-debug.js b/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-debug.js
index c3a6a7a7cd0..79ab71b2d8e 100644
--- a/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-debug.js
+++ b/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-debug.js
@@ -185,12 +185,8 @@ Y.extend(Editor, Y.Base, {
             CSS: CSS
         }));
 
-        // Add a labelled-by attribute to the contenteditable.
-        this.textareaLabel = Y.one('[for="' + this.get('elementid') + '"]');
-        if (this.textareaLabel) {
-            this.textareaLabel.generateID();
-            this.editor.setAttribute('aria-labelledby', this.textareaLabel.get("id"));
-        }
+        // Setup the labels and ARIA labelledby.
+        this._setupLabelling();
 
         // Add everything to the wrapper.
         this.setupToolbar();
@@ -372,6 +368,48 @@ Y.extend(Editor, Y.Base, {
      */
     _registerEventHandle: function(handle) {
         this._eventHandles.push(handle);
+    },
+
+    /**
+     * Setup editor labelling. This includes the aria-labelledby attribute
+     * too.
+     *
+     * @method _setupLabelling
+     * @chainable
+     * @private
+     */
+    _setupLabelling: function() {
+        // Copy the ARIA labelledby attribute from the textarea.
+        var labelledby = this.textarea.getAttribute('aria-labelledby'),
+            labels = [];
+
+        if (labelledby) {
+            // The original textarea has a labelledby field, convert the list of IDs into a list.
+            labels = labelledby.split(' ');
+        }
+
+        // Search for any labels for the original textarea.
+        this.textareaLabel = Y.one('[for="' + this.get('elementid') + '"]');
+        if (this.textareaLabel) {
+            // Ensure that the label has an ID.
+            this.textareaLabel.generateID();
+
+            // Add the label to the list of labels. It may be there already, but we can dedupe the list.
+            labels.push(this.textareaLabel.get('id'));
+
+            // Update the label to point to the Atto editor instead of the original textarea.
+            this.textareaLabel.setAttribute('for', this.editor.getAttribute('id'));
+
+            // Register an event handle for the label - labels don't normally focus on non-input elements so we must add
+            // a click handler.
+            // If something changes what the label is for (e.g. an HTML plugin), then this will cease to match and
+            // standard browser behaviour will resume.
+            this._registerEventHandle(Y.delegate('click', this.focus,
+                    Y.config.doc.body, '[for="' + this.editor.getAttribute('id') + '"]', this));
+        }
+
+        // Add the list of labelling attributes to the atto editor.
+        this.editor.setAttribute('aria-labelledby', Y.Array.unique(labels).join(' '));
     }
 
 }, {
diff --git a/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-min.js b/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-min.js
index 38b4105c459..518c37cf96c 100644
--- a/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-min.js
+++ b/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor-min.js
@@ -1,3 +1,3 @@
-YUI.add("moodle-editor_atto-editor",function(e,t){function i(){i.superclass.constructor.apply(this,arguments)}function s(){}function o(){}function u(){}function a(){}function f(){}function l(){}function c(){}var n="moodle-editor_atto-editor",r={CONTENT:"editor_atto_content",CONTENTWRAPPER:"editor_atto_content_wrap",TOOLBAR:"editor_atto_toolbar",WRAPPER:"editor_atto",HIGHLIGHT:"highlight"};e.extend(i,e.Base,{BLOCK_TAGS:["address","article","aside","audio","blockquote","canvas","dd","div","dl","fieldset","figcaption","figure","footer","form","h1","h2","h3","h4","h5","h6","header","hgroup","hr","noscript","ol","output","p","pre","section","table","tfoot","ul","video"],PLACEHOLDER_CLASS:"atto-tmp-class",ALL_NODES_SELECTOR:"[style],font[face]",FONT_FAMILY:"fontFamily",_wrapper:null,editor:null,textarea:null,textareaLabel:null,plugins:null,_eventHandles:null,initializer:function(){var t;this.textarea=e.one(document.getElementById(this.get("elementid")));if(!this.textarea)return;this._eventHandles=[],this._wrapper=e.Node.create('<div class="'+r.WRAPPER+'" />'),t=e.Handlebars.compile('<div id="{{elementid}}editable" contenteditable="true" role="textbox" spellcheck="true" aria-live="off" class="{{CSS.CONTENT}}" />'),this.editor=e.Node.create(t({elementid:this.get("elementid"),CSS:r})),this.textareaLabel=e.one('[for="'+this.get("elementid")+'"]'),this.textareaLabel&&(this.textareaLabel.generateID(),this.editor.setAttribute("aria-labelledby",this.textareaLabel.get("id"))),this.setupToolbar();var n=e.Node.create('<div class="'+r.CONTENTWRAPPER+'" />');n.appendChild(this.editor),this._wrapper.appendChild(n),this.editor.setStyle("minHeight",20*this.textarea.getAttribute("rows")+8+"px"),e.UA.ie===0&&this.editor.setStyle("height",20*this.textarea.getAttribute("rows")+8+"px"),this.disableCssStyling(),document.queryCommandSupported("DefaultParagraphSeparator")&&document.execCommand("DefaultParagraphSeparator",!1,"p"),this.textarea.get("parentNode").insert(this._wrapper,this.textarea),this.textarea.hide(),this.updateFromTextArea(),this.publishEvents(),this.setupSelectionWatchers(),this.setupAutomaticPolling(),this.setupPlugins()},focus:function(){return this.editor.focus(),this},publishEvents:function(){return this.publish("change",{broadcast:!0,preventable:!0}),this.publish("pluginsloaded",{fireOnce:!0}),this.publish("atto:selectionchanged",{prefix:"atto"}),this},setupAutomaticPolling:function(){return this._registerEventHandle(this.editor.on(["keyup","paste","cut"],this.updateOriginal,this)),this},setupPlugins:function(){this.plugins={};var t=this.get("plugins"),n,r,i,s,o;for(n in t){r=t[n];if(!r.plugins)continue;for(i in r.plugins){s=r.plugins[i],o=e.mix({name:s.name,group:r.group,editor:this.editor,toolbar:this.toolbar,host:this},s);if(typeof e.M["atto_"+s.name]=="undefined")continue;this.plugins[s.name]=new e.M["atto_"+s.name].Button(o)}}return this.fire("pluginsloaded"),this},enablePlugins:function(e){this._setPluginState(!0,e)},disablePlugins:function(e){this._setPluginState(!1,e)},_setPluginState:function(t,n){var r="disableButtons";t&&(r="enableButtons"),n?this.plugins[n][r]():e.Object.each(this.plugins,function(e){e[r]()},this)},_registerEventHandle:function(e){this._eventHandles.push(e)}},{NS:"editor_atto",ATTRS:{elementid:{value:null,writeOnce:!0},plugins:{value:{},writeOnce:!0}}}),e.augment(i,e.EventTarget),e.namespace("M.editor_atto").Editor=i,e.namespace("M.editor_atto.Editor").init=function(t){return new e.M.editor_atto.Editor(t)},s.ATTRS={},s.prototype={_getEmptyContent:function(){return e.UA.ie&&e.UA.ie<10?"<p></p>":"<p><br></p>"},updateFromTextArea:function(){this.editor.setHTML(""),this.editor.append(this.textarea.get("value")),this.cleanEditorHTML(),this.editor.getHTML()===""&&this.editor.setHTML(this._getEmptyContent())},updateOriginal:function(){var e=this.textarea.get("value"),t=this.getCleanHTML();return t===""&&this.isActive()&&(t=this._getEmptyContent()),e!==t&&(this.textarea.set("value",t),this.textarea.simulate("change"),this.fire("change")),this}},e.Base.mix(e.M.editor_atto.Editor,[s]),o.ATTRS={},o.prototype={getCleanHTML:function(){var t=this.editor.cloneNode(!0),n;return e.each(t.all('[id^="yui"]'),function(e){e.removeAttribute("id")}),t.all(".atto_control").remove(!0),n=t.get("innerHTML"),n==="<p></p>"||n==="<p><br></p>"?"":this._cleanHTML(n)},cleanEditorHTML:function(){var e=this.editor.get("innerHTML");return this.editor.set("innerHTML",this._cleanHTML(e)),this},_cleanHTML:function(e){var t=[{regex:/<!--[\s\S]*?-->/gi,replace:""},{regex:/<\\?\?xml[^>]*>/gi,replace:""},{regex:/<\/?\w+:[^>]*>/gi,replace:""},{regex:/\s*MSO[-:][^;"']*;?/gi,replace:""},{regex:/<span[^>]*>(&nbsp;|\s)*<\/span>/gi,replace:""},{regex:/class="Mso[^"]*"/gi,replace:""},{regex:/<(\/?title|\/?meta|\/?style|\/?st\d|\/?head|\/?font|\/?html|\/?body|!\[)[^>]*?>/gi,replace:""},{regex:new RegExp(String.fromCharCode(8220),"gi"),replace:'"'},{regex:new RegExp(String.fromCharCode(8216),"gi"),replace:"'"},{regex:new RegExp(String.fromCharCode(8217),"gi"),replace:"'"},{regex:new RegExp(String.fromCharCode(8211),"gi"),replace:"-"},{regex:new RegExp(String.fromCharCode(8212),"gi"),replace:"--"},{regex:new RegExp(String.fromCharCode(189),"gi"),replace:"1/2"},{regex:new RegExp(String.fromCharCode(188),"gi"),replace:"1/4"},{regex:new RegExp(String.fromCharCode(190),"gi"),replace:"3/4"},{regex:new RegExp(String.fromCharCode(169),"gi"),replace:"(c)"},{regex:new RegExp(String.fromCharCode(174),"gi"),replace:"(r)"},{regex:new RegExp(String.fromCharCode(8230),"gi"),replace:"..."}],n=0;for(n=0;n<t.length;n++)e=e.replace(t[n].regex,t[n].replace);return e}},e.Base.mix(e.M.editor_atto.Editor,[o]),u.ATTRS={},u.prototype={toolbar:null,openMenus:null,setupToolbar:function(){return this.toolbar=e.Node.create('<div class="'+r.TOOLBAR+'" role="toolbar" aria-live="off"/>'),this.openMenus=[],this._wrapper.appendChild(this.toolbar),this.textareaLabel&&this.toolbar.setAttribute("aria-labelledby",this.textareaLabel.get("id")),this.setupToolbarNavigation
-(),this}},e.Base.mix(e.M.editor_atto.Editor,[u]),a.ATTRS={},a.prototype={_tabFocus:null,setupToolbarNavigation:function(){return this._wrapper.delegate("key",this.toolbarKeyboardNavigation,"down:37,39","."+r.TOOLBAR,this),this._wrapper.delegate("focus",function(e){this._setTabFocus(e.currentTarget)},"."+r.TOOLBAR+" button",this),this},toolbarKeyboardNavigation:function(e){e.preventDefault();var t=this.toolbar.all("button"),n=1,r,i=e.target.ancestor("button",!0);e.keyCode===37&&(n=-1),r=this._findFirstFocusable(t,i,n),r&&(r.focus(),this._setTabFocus(r))},_findFirstFocusable:function(e,t,n){var r=0,i,s,o,u;u=e.indexOf(t),u<-1&&(u=0);while(r<e.size()){u+=n,u<0?u=e.size()-1:u>=e.size()&&(u=0),s=e.item(u),r++;if(s.hasAttribute("hidden")||s.hasAttribute("disabled"))continue;i=s.ancestor(".atto_group");if(i.hasAttribute("hidden"))continue;o=s;break}return o},checkTabFocus:function(){return this._tabFocus&&(this._tabFocus.hasAttribute("disabled")||this._tabFocus.hasAttribute("hidden")||this._tabFocus.ancestor(".atto_group").hasAttribute("hidden"))&&(button=this._findFirstFocusable(this.toolbar.all("button"),this._tabFocus,-1),button&&(this._tabFocus.compareTo(document.activeElement)&&button.focus(),this._setTabFocus(button))),this},_setTabFocus:function(e){return this._tabFocus&&this._tabFocus.setAttribute("tabindex","-1"),this._tabFocus=e,this._tabFocus.setAttribute("tabindex",0),this.toolbar.setAttribute("aria-activedescendant",this._tabFocus.generateID()),this}},e.Base.mix(e.M.editor_atto.Editor,[a]),f.ATTRS={},f.prototype={_selections:null,_lastSelection:null,_focusFromClick:!1,setupSelectionWatchers:function(){return this.on("atto:selectionchanged",this.saveSelection,this),this.editor.on("focus",this.restoreSelection,this),this.editor.on("mousedown",function(){this._focusFromClick=!0},this),this.editor.on("blur",function(){this._focusFromClick=!1,this.updateOriginal()},this),e.delegate(["keyup","focus"],function(t){e.soon(e.bind(this._hasSelectionChanged,this,t))},document.body,"#"+this.editor.get("id"),this),e.delegate("gesturemoveend",function(t){e.soon(e.bind(this._hasSelectionChanged,this,t))},document.body,"#"+this.editor.get("id"),{standAlone:!0},this),this},isActive:function(){var t=rangy.createRange(),n=rangy.getSelection();return n.rangeCount?!document.activeElement||e.one(document.activeElement)!==this.editor?!1:(t.selectNode(this.editor.getDOMNode()),t.intersectsRange(n.getRangeAt(0))):!1},getSelectionFromNode:function(e){var t=rangy.createRange();return t.selectNode(e.getDOMNode()),[t]},saveSelection:function(){this.isActive()&&(this._selections=this.getSelection())},restoreSelection:function(){this._focusFromClick||this._selections&&this.setSelection(this._selections),this._focusFromClick=!1},getSelection:function(){return rangy.getSelection().getAllRanges()},selectionContainsNode:function(e){return rangy.getSelection().containsNode(e.getDOMNode(),!0)},selectionFilterMatches:function(e,t,n){typeof n=="undefined"&&(n=!0),t||(t=this.getSelectedNodes());var r=t.size()>0,i=!1,s=this.editor,o=function(e){return e===s};return s.one(e)?(t.each(function(t){if(n){if(!r||!t.ancestor(e,!0,o))r=!1}else!i&&t.ancestor(e,!0,o)&&(i=!0)},this),n?r:i):!1},getSelectedNodes:function(){var t=new e.NodeList,n,r,i,s,o;r=rangy.getSelection(),r.rangeCount?i=r.getRangeAt(0):i=rangy.createRange(),i.collapsed&&i.commonAncestorContainer!==this.editor.getDOMNode()&&i.commonAncestorContainer!==e.config.doc&&(i=i.cloneRange(),i.selectNode(i.commonAncestorContainer)),n=i.getNodes();for(o=0;o<n.length;o++)s=e.one(n[o]),this.editor.contains(s)&&t.push(s);return t},_hasSelectionChanged:function(e){var t=rangy.getSelection(),n,r=!1;return t.rangeCount?n=t.getRangeAt(0):n=rangy.createRange(),this._lastSelection&&!this._lastSelection.equals(n)?(r=!0,this._fireSelectionChanged(e)):(this._lastSelection=n,r)},_fireSelectionChanged:function(e){this.fire("atto:selectionchanged",{event:e,selectedNodes:this.getSelectedNodes()})},getSelectionParentNode:function(){var e=rangy.getSelection();return e.rangeCount?e.getRangeAt(0).commonAncestorContainer:!1},setSelection:function(e){var t=rangy.getSelection();t.setRanges(e)},insertContentAtFocusPoint:function(t){var n=rangy.getSelection(),r,i=e.Node.create(t);n.rangeCount&&(r=n.getRangeAt(0)),r&&(r.deleteContents(),r.insertNode(i.getDOMNode()))}},e.Base.mix(e.M.editor_atto.Editor,[f]),l.ATTRS={},l.prototype={disableCssStyling:function(){try{document.execCommand("styleWithCSS",0,!1)}catch(e){try{document.execCommand("useCSS",0,!0)}catch(t){try{document.execCommand("styleWithCSS",!1,!1)}catch(n){}}}},enableCssStyling:function(){try{document.execCommand("styleWithCSS",0,!0)}catch(e){try{document.execCommand("useCSS",0,!1)}catch(t){try{document.execCommand("styleWithCSS",!1,!0)}catch(n){}}}},toggleInlineSelectionClass:function(e){var t=e.join(" "),n=this.getSelection(),r=rangy.createCssClassApplier(t,{normalize:!0});r.toggleSelection(),this.setSelection(n)},formatSelectionInlineStyle:function(e){var t=this.PLACEHOLDER_CLASS,n=this.getSelection(),r=rangy.createCssClassApplier(t,{normalize:!0});r.applyToSelection(),this.editor.all("."+t).each(function(n){n.removeClass(t).setStyles(e)},this),this.setSelection(n)},formatSelectionBlock:function(t,n){var r=this.getSelectionParentNode(),i,s,o,u,a,f;if(!r)return!1;i=this.editor,r=e.one(r),s=r.ancestor(function(e){var t=e.get("tagName");return t&&(t=t.toLowerCase()),e===i||t==="td"||t==="th"},!0),s&&(i=s),o=r.ancestor(this.BLOCK_TAGS.join(", "),!0),o&&(a=o.ancestor(function(e){return e===i},!1),a||(o=!1)),o||(u=e.Node.create("<p></p>"),i.get("childNodes").each(function(e){u.append(e.remove())}),i.append(u),o=u),t&&t!==""&&(f=e.Node.create("<"+t+"></"+t+">"),f.setAttrs(o.getAttrs()),o.get("childNodes").each(function(e){e.remove(),f.append(e)}),o.replace(f),o=f),n&&o.setAttrs(n);var l=this.getSelectionFromNode(o);return this.setSelection(l),o}},e.Base.mix(e.M.editor_atto.Editor,[l]),c.ATTRS={filepickeroptions:{value:{}}},c.prototype={canShowFilepicker
-:function(e){return typeof this.get("filepickeroptions")[e]!="undefined"},showFilepicker:function(t,n,r){var i=this;e.use("core_filepicker",function(e){var s=e.clone(i.get("filepickeroptions")[t],!0);s.formcallback=n,r&&(s.magicscope=r),M.core_filepicker.show(e,s)})}},e.Base.mix(e.M.editor_atto.Editor,[c])},"@VERSION@",{requires:["node","io","overlay","escape","event","event-simulate","event-custom","yui-throttle","moodle-core-notification-dialogue","moodle-editor_atto-rangy","handlebars","timers"]});
+YUI.add("moodle-editor_atto-editor",function(e,t){function i(){i.superclass.constructor.apply(this,arguments)}function s(){}function o(){}function u(){}function a(){}function f(){}function l(){}function c(){}var n="moodle-editor_atto-editor",r={CONTENT:"editor_atto_content",CONTENTWRAPPER:"editor_atto_content_wrap",TOOLBAR:"editor_atto_toolbar",WRAPPER:"editor_atto",HIGHLIGHT:"highlight"};e.extend(i,e.Base,{BLOCK_TAGS:["address","article","aside","audio","blockquote","canvas","dd","div","dl","fieldset","figcaption","figure","footer","form","h1","h2","h3","h4","h5","h6","header","hgroup","hr","noscript","ol","output","p","pre","section","table","tfoot","ul","video"],PLACEHOLDER_CLASS:"atto-tmp-class",ALL_NODES_SELECTOR:"[style],font[face]",FONT_FAMILY:"fontFamily",_wrapper:null,editor:null,textarea:null,textareaLabel:null,plugins:null,_eventHandles:null,initializer:function(){var t;this.textarea=e.one(document.getElementById(this.get("elementid")));if(!this.textarea)return;this._eventHandles=[],this._wrapper=e.Node.create('<div class="'+r.WRAPPER+'" />'),t=e.Handlebars.compile('<div id="{{elementid}}editable" contenteditable="true" role="textbox" spellcheck="true" aria-live="off" class="{{CSS.CONTENT}}" />'),this.editor=e.Node.create(t({elementid:this.get("elementid"),CSS:r})),this._setupLabelling(),this.setupToolbar();var n=e.Node.create('<div class="'+r.CONTENTWRAPPER+'" />');n.appendChild(this.editor),this._wrapper.appendChild(n),this.editor.setStyle("minHeight",20*this.textarea.getAttribute("rows")+8+"px"),e.UA.ie===0&&this.editor.setStyle("height",20*this.textarea.getAttribute("rows")+8+"px"),this.disableCssStyling(),document.queryCommandSupported("DefaultParagraphSeparator")&&document.execCommand("DefaultParagraphSeparator",!1,"p"),this.textarea.get("parentNode").insert(this._wrapper,this.textarea),this.textarea.hide(),this.updateFromTextArea(),this.publishEvents(),this.setupSelectionWatchers(),this.setupAutomaticPolling(),this.setupPlugins()},focus:function(){return this.editor.focus(),this},publishEvents:function(){return this.publish("change",{broadcast:!0,preventable:!0}),this.publish("pluginsloaded",{fireOnce:!0}),this.publish("atto:selectionchanged",{prefix:"atto"}),this},setupAutomaticPolling:function(){return this._registerEventHandle(this.editor.on(["keyup","paste","cut"],this.updateOriginal,this)),this},setupPlugins:function(){this.plugins={};var t=this.get("plugins"),n,r,i,s,o;for(n in t){r=t[n];if(!r.plugins)continue;for(i in r.plugins){s=r.plugins[i],o=e.mix({name:s.name,group:r.group,editor:this.editor,toolbar:this.toolbar,host:this},s);if(typeof e.M["atto_"+s.name]=="undefined")continue;this.plugins[s.name]=new e.M["atto_"+s.name].Button(o)}}return this.fire("pluginsloaded"),this},enablePlugins:function(e){this._setPluginState(!0,e)},disablePlugins:function(e){this._setPluginState(!1,e)},_setPluginState:function(t,n){var r="disableButtons";t&&(r="enableButtons"),n?this.plugins[n][r]():e.Object.each(this.plugins,function(e){e[r]()},this)},_registerEventHandle:function(e){this._eventHandles.push(e)},_setupLabelling:function(){var t=this.textarea.getAttribute("aria-labelledby"),n=[];t&&(n=t.split(" ")),this.textareaLabel=e.one('[for="'+this.get("elementid")+'"]'),this.textareaLabel&&(this.textareaLabel.generateID(),n.push(this.textareaLabel.get("id")),this.textareaLabel.setAttribute("for",this.editor.getAttribute("id")),this._registerEventHandle(e.delegate("click",this.focus,e.config.doc.body,'[for="'+this.editor.getAttribute("id")+'"]',this))),this.editor.setAttribute("aria-labelledby",e.Array.unique(n).join(" "))}},{NS:"editor_atto",ATTRS:{elementid:{value:null,writeOnce:!0},plugins:{value:{},writeOnce:!0}}}),e.augment(i,e.EventTarget),e.namespace("M.editor_atto").Editor=i,e.namespace("M.editor_atto.Editor").init=function(t){return new e.M.editor_atto.Editor(t)},s.ATTRS={},s.prototype={_getEmptyContent:function(){return e.UA.ie&&e.UA.ie<10?"<p></p>":"<p><br></p>"},updateFromTextArea:function(){this.editor.setHTML(""),this.editor.append(this.textarea.get("value")),this.cleanEditorHTML(),this.editor.getHTML()===""&&this.editor.setHTML(this._getEmptyContent())},updateOriginal:function(){var e=this.textarea.get("value"),t=this.getCleanHTML();return t===""&&this.isActive()&&(t=this._getEmptyContent()),e!==t&&(this.textarea.set("value",t),this.textarea.simulate("change"),this.fire("change")),this}},e.Base.mix(e.M.editor_atto.Editor,[s]),o.ATTRS={},o.prototype={getCleanHTML:function(){var t=this.editor.cloneNode(!0),n;return e.each(t.all('[id^="yui"]'),function(e){e.removeAttribute("id")}),t.all(".atto_control").remove(!0),n=t.get("innerHTML"),n==="<p></p>"||n==="<p><br></p>"?"":this._cleanHTML(n)},cleanEditorHTML:function(){var e=this.editor.get("innerHTML");return this.editor.set("innerHTML",this._cleanHTML(e)),this},_cleanHTML:function(e){var t=[{regex:/<!--[\s\S]*?-->/gi,replace:""},{regex:/<\\?\?xml[^>]*>/gi,replace:""},{regex:/<\/?\w+:[^>]*>/gi,replace:""},{regex:/\s*MSO[-:][^;"']*;?/gi,replace:""},{regex:/<span[^>]*>(&nbsp;|\s)*<\/span>/gi,replace:""},{regex:/class="Mso[^"]*"/gi,replace:""},{regex:/<(\/?title|\/?meta|\/?style|\/?st\d|\/?head|\/?font|\/?html|\/?body|!\[)[^>]*?>/gi,replace:""},{regex:new RegExp(String.fromCharCode(8220),"gi"),replace:'"'},{regex:new RegExp(String.fromCharCode(8216),"gi"),replace:"'"},{regex:new RegExp(String.fromCharCode(8217),"gi"),replace:"'"},{regex:new RegExp(String.fromCharCode(8211),"gi"),replace:"-"},{regex:new RegExp(String.fromCharCode(8212),"gi"),replace:"--"},{regex:new RegExp(String.fromCharCode(189),"gi"),replace:"1/2"},{regex:new RegExp(String.fromCharCode(188),"gi"),replace:"1/4"},{regex:new RegExp(String.fromCharCode(190),"gi"),replace:"3/4"},{regex:new RegExp(String.fromCharCode(169),"gi"),replace:"(c)"},{regex:new RegExp(String.fromCharCode(174),"gi"),replace:"(r)"},{regex:new RegExp(String.fromCharCode(8230),"gi"),replace:"..."}],n=0;for(n=0;n<t.length;n++)e=e.replace(t[n].regex,t[n].replace);return e}},e.Base.mix(e.M.editor_atto
+.Editor,[o]),u.ATTRS={},u.prototype={toolbar:null,openMenus:null,setupToolbar:function(){return this.toolbar=e.Node.create('<div class="'+r.TOOLBAR+'" role="toolbar" aria-live="off"/>'),this.openMenus=[],this._wrapper.appendChild(this.toolbar),this.textareaLabel&&this.toolbar.setAttribute("aria-labelledby",this.textareaLabel.get("id")),this.setupToolbarNavigation(),this}},e.Base.mix(e.M.editor_atto.Editor,[u]),a.ATTRS={},a.prototype={_tabFocus:null,setupToolbarNavigation:function(){return this._wrapper.delegate("key",this.toolbarKeyboardNavigation,"down:37,39","."+r.TOOLBAR,this),this._wrapper.delegate("focus",function(e){this._setTabFocus(e.currentTarget)},"."+r.TOOLBAR+" button",this),this},toolbarKeyboardNavigation:function(e){e.preventDefault();var t=this.toolbar.all("button"),n=1,r,i=e.target.ancestor("button",!0);e.keyCode===37&&(n=-1),r=this._findFirstFocusable(t,i,n),r&&(r.focus(),this._setTabFocus(r))},_findFirstFocusable:function(e,t,n){var r=0,i,s,o,u;u=e.indexOf(t),u<-1&&(u=0);while(r<e.size()){u+=n,u<0?u=e.size()-1:u>=e.size()&&(u=0),s=e.item(u),r++;if(s.hasAttribute("hidden")||s.hasAttribute("disabled"))continue;i=s.ancestor(".atto_group");if(i.hasAttribute("hidden"))continue;o=s;break}return o},checkTabFocus:function(){return this._tabFocus&&(this._tabFocus.hasAttribute("disabled")||this._tabFocus.hasAttribute("hidden")||this._tabFocus.ancestor(".atto_group").hasAttribute("hidden"))&&(button=this._findFirstFocusable(this.toolbar.all("button"),this._tabFocus,-1),button&&(this._tabFocus.compareTo(document.activeElement)&&button.focus(),this._setTabFocus(button))),this},_setTabFocus:function(e){return this._tabFocus&&this._tabFocus.setAttribute("tabindex","-1"),this._tabFocus=e,this._tabFocus.setAttribute("tabindex",0),this.toolbar.setAttribute("aria-activedescendant",this._tabFocus.generateID()),this}},e.Base.mix(e.M.editor_atto.Editor,[a]),f.ATTRS={},f.prototype={_selections:null,_lastSelection:null,_focusFromClick:!1,setupSelectionWatchers:function(){return this.on("atto:selectionchanged",this.saveSelection,this),this.editor.on("focus",this.restoreSelection,this),this.editor.on("mousedown",function(){this._focusFromClick=!0},this),this.editor.on("blur",function(){this._focusFromClick=!1,this.updateOriginal()},this),e.delegate(["keyup","focus"],function(t){e.soon(e.bind(this._hasSelectionChanged,this,t))},document.body,"#"+this.editor.get("id"),this),e.delegate("gesturemoveend",function(t){e.soon(e.bind(this._hasSelectionChanged,this,t))},document.body,"#"+this.editor.get("id"),{standAlone:!0},this),this},isActive:function(){var t=rangy.createRange(),n=rangy.getSelection();return n.rangeCount?!document.activeElement||e.one(document.activeElement)!==this.editor?!1:(t.selectNode(this.editor.getDOMNode()),t.intersectsRange(n.getRangeAt(0))):!1},getSelectionFromNode:function(e){var t=rangy.createRange();return t.selectNode(e.getDOMNode()),[t]},saveSelection:function(){this.isActive()&&(this._selections=this.getSelection())},restoreSelection:function(){this._focusFromClick||this._selections&&this.setSelection(this._selections),this._focusFromClick=!1},getSelection:function(){return rangy.getSelection().getAllRanges()},selectionContainsNode:function(e){return rangy.getSelection().containsNode(e.getDOMNode(),!0)},selectionFilterMatches:function(e,t,n){typeof n=="undefined"&&(n=!0),t||(t=this.getSelectedNodes());var r=t.size()>0,i=!1,s=this.editor,o=function(e){return e===s};return s.one(e)?(t.each(function(t){if(n){if(!r||!t.ancestor(e,!0,o))r=!1}else!i&&t.ancestor(e,!0,o)&&(i=!0)},this),n?r:i):!1},getSelectedNodes:function(){var t=new e.NodeList,n,r,i,s,o;r=rangy.getSelection(),r.rangeCount?i=r.getRangeAt(0):i=rangy.createRange(),i.collapsed&&i.commonAncestorContainer!==this.editor.getDOMNode()&&i.commonAncestorContainer!==e.config.doc&&(i=i.cloneRange(),i.selectNode(i.commonAncestorContainer)),n=i.getNodes();for(o=0;o<n.length;o++)s=e.one(n[o]),this.editor.contains(s)&&t.push(s);return t},_hasSelectionChanged:function(e){var t=rangy.getSelection(),n,r=!1;return t.rangeCount?n=t.getRangeAt(0):n=rangy.createRange(),this._lastSelection&&!this._lastSelection.equals(n)?(r=!0,this._fireSelectionChanged(e)):(this._lastSelection=n,r)},_fireSelectionChanged:function(e){this.fire("atto:selectionchanged",{event:e,selectedNodes:this.getSelectedNodes()})},getSelectionParentNode:function(){var e=rangy.getSelection();return e.rangeCount?e.getRangeAt(0).commonAncestorContainer:!1},setSelection:function(e){var t=rangy.getSelection();t.setRanges(e)},insertContentAtFocusPoint:function(t){var n=rangy.getSelection(),r,i=e.Node.create(t);n.rangeCount&&(r=n.getRangeAt(0)),r&&(r.deleteContents(),r.insertNode(i.getDOMNode()))}},e.Base.mix(e.M.editor_atto.Editor,[f]),l.ATTRS={},l.prototype={disableCssStyling:function(){try{document.execCommand("styleWithCSS",0,!1)}catch(e){try{document.execCommand("useCSS",0,!0)}catch(t){try{document.execCommand("styleWithCSS",!1,!1)}catch(n){}}}},enableCssStyling:function(){try{document.execCommand("styleWithCSS",0,!0)}catch(e){try{document.execCommand("useCSS",0,!1)}catch(t){try{document.execCommand("styleWithCSS",!1,!0)}catch(n){}}}},toggleInlineSelectionClass:function(e){var t=e.join(" "),n=this.getSelection(),r=rangy.createCssClassApplier(t,{normalize:!0});r.toggleSelection(),this.setSelection(n)},formatSelectionInlineStyle:function(e){var t=this.PLACEHOLDER_CLASS,n=this.getSelection(),r=rangy.createCssClassApplier(t,{normalize:!0});r.applyToSelection(),this.editor.all("."+t).each(function(n){n.removeClass(t).setStyles(e)},this),this.setSelection(n)},formatSelectionBlock:function(t,n){var r=this.getSelectionParentNode(),i,s,o,u,a,f;if(!r)return!1;i=this.editor,r=e.one(r),s=r.ancestor(function(e){var t=e.get("tagName");return t&&(t=t.toLowerCase()),e===i||t==="td"||t==="th"},!0),s&&(i=s),o=r.ancestor(this.BLOCK_TAGS.join(", "),!0),o&&(a=o.ancestor(function(e){return e===i},!1),a||(o=!1)),o||(u=e.Node.create("<p></p>"),i.get("childNodes").each(function(e){u.append(e.remove
+())}),i.append(u),o=u),t&&t!==""&&(f=e.Node.create("<"+t+"></"+t+">"),f.setAttrs(o.getAttrs()),o.get("childNodes").each(function(e){e.remove(),f.append(e)}),o.replace(f),o=f),n&&o.setAttrs(n);var l=this.getSelectionFromNode(o);return this.setSelection(l),o}},e.Base.mix(e.M.editor_atto.Editor,[l]),c.ATTRS={filepickeroptions:{value:{}}},c.prototype={canShowFilepicker:function(e){return typeof this.get("filepickeroptions")[e]!="undefined"},showFilepicker:function(t,n,r){var i=this;e.use("core_filepicker",function(e){var s=e.clone(i.get("filepickeroptions")[t],!0);s.formcallback=n,r&&(s.magicscope=r),M.core_filepicker.show(e,s)})}},e.Base.mix(e.M.editor_atto.Editor,[c])},"@VERSION@",{requires:["node","io","overlay","escape","event","event-simulate","event-custom","yui-throttle","moodle-core-notification-dialogue","moodle-editor_atto-rangy","handlebars","timers"]});
diff --git a/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor.js b/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor.js
index b2d74422396..4fd7f65acb4 100644
--- a/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor.js
+++ b/lib/editor/atto/yui/build/moodle-editor_atto-editor/moodle-editor_atto-editor.js
@@ -183,12 +183,8 @@ Y.extend(Editor, Y.Base, {
             CSS: CSS
         }));
 
-        // Add a labelled-by attribute to the contenteditable.
-        this.textareaLabel = Y.one('[for="' + this.get('elementid') + '"]');
-        if (this.textareaLabel) {
-            this.textareaLabel.generateID();
-            this.editor.setAttribute('aria-labelledby', this.textareaLabel.get("id"));
-        }
+        // Setup the labels and ARIA labelledby.
+        this._setupLabelling();
 
         // Add everything to the wrapper.
         this.setupToolbar();
@@ -369,6 +365,48 @@ Y.extend(Editor, Y.Base, {
      */
     _registerEventHandle: function(handle) {
         this._eventHandles.push(handle);
+    },
+
+    /**
+     * Setup editor labelling. This includes the aria-labelledby attribute
+     * too.
+     *
+     * @method _setupLabelling
+     * @chainable
+     * @private
+     */
+    _setupLabelling: function() {
+        // Copy the ARIA labelledby attribute from the textarea.
+        var labelledby = this.textarea.getAttribute('aria-labelledby'),
+            labels = [];
+
+        if (labelledby) {
+            // The original textarea has a labelledby field, convert the list of IDs into a list.
+            labels = labelledby.split(' ');
+        }
+
+        // Search for any labels for the original textarea.
+        this.textareaLabel = Y.one('[for="' + this.get('elementid') + '"]');
+        if (this.textareaLabel) {
+            // Ensure that the label has an ID.
+            this.textareaLabel.generateID();
+
+            // Add the label to the list of labels. It may be there already, but we can dedupe the list.
+            labels.push(this.textareaLabel.get('id'));
+
+            // Update the label to point to the Atto editor instead of the original textarea.
+            this.textareaLabel.setAttribute('for', this.editor.getAttribute('id'));
+
+            // Register an event handle for the label - labels don't normally focus on non-input elements so we must add
+            // a click handler.
+            // If something changes what the label is for (e.g. an HTML plugin), then this will cease to match and
+            // standard browser behaviour will resume.
+            this._registerEventHandle(Y.delegate('click', this.focus,
+                    Y.config.doc.body, '[for="' + this.editor.getAttribute('id') + '"]', this));
+        }
+
+        // Add the list of labelling attributes to the atto editor.
+        this.editor.setAttribute('aria-labelledby', Y.Array.unique(labels).join(' '));
     }
 
 }, {
diff --git a/lib/editor/atto/yui/src/editor/js/editor.js b/lib/editor/atto/yui/src/editor/js/editor.js
index 931086c04a5..2e3ae0c36b0 100644
--- a/lib/editor/atto/yui/src/editor/js/editor.js
+++ b/lib/editor/atto/yui/src/editor/js/editor.js
@@ -183,12 +183,8 @@ Y.extend(Editor, Y.Base, {
             CSS: CSS
         }));
 
-        // Add a labelled-by attribute to the contenteditable.
-        this.textareaLabel = Y.one('[for="' + this.get('elementid') + '"]');
-        if (this.textareaLabel) {
-            this.textareaLabel.generateID();
-            this.editor.setAttribute('aria-labelledby', this.textareaLabel.get("id"));
-        }
+        // Setup the labels and ARIA labelledby.
+        this._setupLabelling();
 
         // Add everything to the wrapper.
         this.setupToolbar();
@@ -370,6 +366,48 @@ Y.extend(Editor, Y.Base, {
      */
     _registerEventHandle: function(handle) {
         this._eventHandles.push(handle);
+    },
+
+    /**
+     * Setup editor labelling. This includes the aria-labelledby attribute
+     * too.
+     *
+     * @method _setupLabelling
+     * @chainable
+     * @private
+     */
+    _setupLabelling: function() {
+        // Copy the ARIA labelledby attribute from the textarea.
+        var labelledby = this.textarea.getAttribute('aria-labelledby'),
+            labels = [];
+
+        if (labelledby) {
+            // The original textarea has a labelledby field, convert the list of IDs into a list.
+            labels = labelledby.split(' ');
+        }
+
+        // Search for any labels for the original textarea.
+        this.textareaLabel = Y.one('[for="' + this.get('elementid') + '"]');
+        if (this.textareaLabel) {
+            // Ensure that the label has an ID.
+            this.textareaLabel.generateID();
+
+            // Add the label to the list of labels. It may be there already, but we can dedupe the list.
+            labels.push(this.textareaLabel.get('id'));
+
+            // Update the label to point to the Atto editor instead of the original textarea.
+            this.textareaLabel.setAttribute('for', this.editor.getAttribute('id'));
+
+            // Register an event handle for the label - labels don't normally focus on non-input elements so we must add
+            // a click handler.
+            // If something changes what the label is for (e.g. an HTML plugin), then this will cease to match and
+            // standard browser behaviour will resume.
+            this._registerEventHandle(Y.delegate('click', this.focus,
+                    Y.config.doc.body, '[for="' + this.editor.getAttribute('id') + '"]', this));
+        }
+
+        // Add the list of labelling attributes to the atto editor.
+        this.editor.setAttribute('aria-labelledby', Y.Array.unique(labels).join(' '));
     }
 
 }, {