diff --git a/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button-debug.js b/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button-debug.js
index 83cdc400359..8595032d14c 100644
--- a/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button-debug.js
+++ b/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button-debug.js
@@ -423,7 +423,6 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
         var textarea = this._content.one(SELECTORS.EQUATION_TEXT),
             equation = textarea.get('value'),
             url,
-            preview,
             currentPos = textarea.get('selectionStart'),
             prefix = '',
             cursorLatex = '\\Downarrow ',
@@ -455,7 +454,6 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
         this._lastCursorPos = currentPos;
         equation = prefix + equation.substring(0, currentPos) + cursorLatex + equation.substring(currentPos);
 
-        var previewNode = this._content.one(SELECTORS.EQUATION_PREVIEW);
         equation = DELIMITERS.START + ' ' + equation + ' ' + DELIMITERS.END;
         // Make an ajax request to the filter.
         url = M.cfg.wwwroot + '/lib/editor/atto/plugins/equation/ajax.php';
@@ -466,13 +464,30 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
             text: equation
         };
 
-        preview = Y.io(url, {
-            sync: true,
-            data: params
+        Y.io(url, {
+            context: this,
+            data: params,
+            timeout: 500,
+            on: {
+                complete: this._loadPreview
+            }
         });
+    },
+
+    /**
+     * Load returned preview text into preview
+     *
+     * @param {String} id
+     * @param {EventFacade} e
+     * @method _loadPreview
+     * @private
+     */
+    _loadPreview: function(id, preview) {
+        var previewNode = this._content.one(SELECTORS.EQUATION_PREVIEW);
 
         if (preview.status === 200) {
             previewNode.setHTML(preview.responseText);
+
             Y.fire(M.core.event.FILTER_CONTENT_UPDATED, {nodes: (new Y.NodeList(previewNode))});
         }
     },
@@ -487,6 +502,7 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
      */
     _getDialogueContent: function() {
         var library = this._getLibraryContent(),
+            throttledUpdate = this._throttle(this._updatePreview, 500),
             template = Y.Handlebars.compile(TEMPLATES.FORM);
 
         this._content = Y.Node.create(template({
@@ -509,9 +525,9 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
         this._content.delegate('key', this._groupNavigation, 'down:37,39', SELECTORS.LIBRARY_BUTTON, this);
 
         this._content.one(SELECTORS.SUBMIT).on('click', this._setEquation, this);
-        this._content.one(SELECTORS.EQUATION_TEXT).on('valuechange', this._throttle(this._updatePreview, 500), this);
-        this._content.one(SELECTORS.EQUATION_TEXT).on('mouseup', this._throttle(this._updatePreview, 500), this);
-        this._content.one(SELECTORS.EQUATION_TEXT).on('keyup', this._throttle(this._updatePreview, 500), this);
+        this._content.one(SELECTORS.EQUATION_TEXT).on('valuechange', throttledUpdate, this);
+        this._content.one(SELECTORS.EQUATION_TEXT).on('mouseup', throttledUpdate, this);
+        this._content.one(SELECTORS.EQUATION_TEXT).on('keyup', throttledUpdate, this);
         this._content.delegate('click', this._selectLibraryItem, SELECTORS.LIBRARY_BUTTON, this);
 
         return this._content;
diff --git a/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button-min.js b/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button-min.js
index 99fc109f417..e82600d3e89 100644
--- a/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button-min.js
+++ b/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button-min.js
@@ -1,2 +1,2 @@
-YUI.add("moodle-atto_equation-button",function(e,t){var n="atto_equation",r="atto_equation",i={EQUATION_TEXT:"atto_equation_equation",EQUATION_PREVIEW:"atto_equation_preview",SUBMIT:"atto_equation_submit",LIBRARY:"atto_equation_library",LIBRARY_GROUPS:"atto_equation_groups",LIBRARY_GROUP_PREFIX:"atto_equation_group"},s={LIBRARY:"."+i.LIBRARY,LIBRARY_GROUP:"."+i.LIBRARY_GROUPS+" > div > div",EQUATION_TEXT:"."+i.EQUATION_TEXT,EQUATION_PREVIEW:"."+i.EQUATION_PREVIEW,SUBMIT:"."+i.SUBMIT,LIBRARY_BUTTON:"."+i.LIBRARY+" button"},o={START:"\\(",END:"\\)"},u={FORM:'<form class="atto_form">{{{library}}}<label for="{{elementid}}_{{CSS.EQUATION_TEXT}}">{{{get_string "editequation" component texdocsurl}}}</label><textarea class="fullwidth {{CSS.EQUATION_TEXT}}" id="{{elementid}}_{{CSS.EQUATION_TEXT}}" rows="8"></textarea><br/><label for="{{elementid}}_{{CSS.EQUATION_PREVIEW}}">{{get_string "preview" component}}</label><div describedby="{{elementid}}_cursorinfo" class="well well-small fullwidth {{CSS.EQUATION_PREVIEW}}" id="{{elementid}}_{{CSS.EQUATION_PREVIEW}}"></div><div id="{{elementid}}_cursorinfo">{{get_string "cursorinfo" component}}</div><div class="mdl-align"><br/><button class="{{CSS.SUBMIT}}">{{get_string "saveequation" component}}</button></div></form>',LIBRARY:'<div class="{{CSS.LIBRARY}}"><ul>{{#each library}}<li><a href="#{{../elementid}}_{{../CSS.LIBRARY_GROUP_PREFIX}}_{{@key}}">{{get_string groupname ../component}}</a></li>{{/each}}</ul><div class="{{CSS.LIBRARY_GROUPS}}">{{#each library}}<div id="{{../elementid}}_{{../CSS.LIBRARY_GROUP_PREFIX}}_{{@key}}"><div role="toolbar">{{#split "\n" elements}}<button tabindex="-1" data-tex="{{this}}" aria-label="{{this}}" title="{{this}}">{{../../DELIMITERS.START}}{{this}}{{../../DELIMITERS.END}}</button>{{/split}}</div></div>{{/each}}</div></div>'};e.namespace("M.atto_equation").Button=e.Base.create("button",e.M.editor_atto.EditorPlugin,[],{_currentSelection:null,_lastCursorPos:0,_content:null,_sourceEquation:null,_groupFocus:null,_equationPatterns:[/\$\$([\S\s]+?)\$\$/,/\\\(([\S\s]+?)\\\)/,/\\\[([\S\s]+?)\\\]/,/\[tex\]([\S\s]+?)\[\/tex\]/],initializer:function(){this._groupFocus={},this.get("texfilteractive")&&(this.addButton({icon:"e/math",callback:this._displayDialogue}),this.get("host").on("atto:selectionchanged",function(){this._resolveEquation()?this.highlightButtons():this.unHighlightButtons()},this),this.editor.all("tex").each(function(t){var n=e.Node.create("<span>"+o.START+" "+t.get("text")+" "+o.END+"</span>");t.replace(n)}))},_displayDialogue:function(){this._currentSelection=this.get("host").getSelection();if(this._currentSelection===!1)return;var t=this._resolveEquation(),r=this.getDialogue({headerContent:M.util.get_string("pluginname",n),focusAfterHide:!0,width:600,focusOnShowSelector:s.EQUATION_TEXT}),i=this._getDialogueContent();r.set("bodyContent",i);var o=i.one(s.LIBRARY),u=new e.TabView({srcNode:o});u.render(),r.show(),e.fire(M.core.event.FILTER_CONTENT_UPDATED,{nodes:new e.NodeList(r.get("boundingBox"))}),t&&i.one(s.EQUATION_TEXT).set("text",t),this._updatePreview(!1)},_resolveEquation:function(){var t=this.get("host").getSelectionParentNode(),n=this.get("host").getSelection(),r,i=!1;return this.get("host").isActive()?t?!n||n.length===0?!1:(this.sourceEquation=null,n=n[0],r=e.one(t).get("text"),e.Array.find(this._equationPatterns,function(t){var s=r.match(new RegExp(t.source,"g"));if(s&&s.length)return e.Array.find(s,function(e){var s=0;while(r.indexOf(e,s)!==-1){var o=r.indexOf(e,s),u=o+e.length,a=n.startOffset>=o&&n.startOffset<u,f=n.endOffset<=u&&n.endOffset>o;if(a&&f){var l=e.match(t);if(l&&l.length){var c=r.indexOf(l[1],o),h=c+l[1].length;return i=l[1],this.sourceEquation={startOuterPosition:o,endOuterPosition:u,outerMatch:e,startInnerPosition:c,endInnerPosition:h,innerMatch:l},!0}}s=u}},this)},this),i!==!1&&(i=i.trim()),i):!1:!1},_setEquation:function(t){var n,r,i,s,u;u=this.get("host"),t.preventDefault(),this.getDialogue({focusAfterHide:null}).hide(),n=t.currentTarget.ancestor(".atto_form").one("textarea"),s=n.get("value"),s!==""&&(u.setSelection(this._currentSelection),this.sourceEquation?(r=e.one(u.getSelectionParentNode()),i=r.get("text"),s=" "+s+" ",newText=i.slice(0,this.sourceEquation.startInnerPosition)+s+i.slice(this.sourceEquation.endInnerPosition),r.set("text",newText)):(s=o.START+" "+s+" "+o.END,u.insertContentAtFocusPoint(s)),this.markUpdated())},_throttle:function(e,t){var n=null;return function(){var r=this,i=arguments;clearTimeout(n),n=setTimeout(function(){e.apply(r,i)},t)}},_updatePreview:function(t){var n=this._content.one(s.EQUATION_TEXT),r=n.get("value"),i,u,a=n.get("selectionStart"),f="",l="\\Downarrow ",c,h;t&&t.preventDefault(),a||(a=0);while(r.charAt(a)==="\\"&&a>=0)a-=1;c=/[a-zA-Z\{\}]/;if(a!==0)while(c.test(r.charAt(a))&&a<r.length&&c.test(r.charAt(a-1)))a+=1;this._lastCursorPos=a,r=f+r.substring(0,a)+l+r.substring(a);var p=this._content.one(s.EQUATION_PREVIEW);r=o.START+" "+r+" "+o.END,i=M.cfg.wwwroot+"/lib/editor/atto/plugins/equation/ajax.php",h={sesskey:M.cfg.sesskey,contextid:this.get("contextid"),action:"filtertext",text:r},u=e.io(i,{sync:!0,data:h}),u.status===200&&(p.setHTML(u.responseText),e.fire(M.core.event.FILTER_CONTENT_UPDATED,{nodes:new e.NodeList(p)}))},_getDialogueContent:function(){var t=this._getLibraryContent(),r=e.Handlebars.compile(u.FORM);return this._content=e.Node.create(r({elementid:this.get("host").get("elementid"),component:n,library:t,texdocsurl:this.get("texdocsurl"),CSS:i})),this._content.all(s.LIBRARY_GROUP).each(function(e){this._setGroupTabFocus(e,e.one("button")),e.all("button a").setAttribute("tabindex","-1")},this),this._content.delegate("key",this._groupNavigation,"down:37,39",s.LIBRARY_BUTTON,this),this._content.one(s.SUBMIT).on("click",this._setEquation,this),this._content.one(s.EQUATION_TEXT).on("valuechange",this._throttle(this._updatePreview,500),this),this._content.one(s.EQUATION_TEXT).on("mouseup",this._throttle(this._updatePreview,500),this),this.
-_content.one(s.EQUATION_TEXT).on("keyup",this._throttle(this._updatePreview,500),this),this._content.delegate("click",this._selectLibraryItem,s.LIBRARY_BUTTON,this),this._content},_groupNavigation:function(e){e.preventDefault();var t=e.currentTarget,n=t.get("parentNode"),r=n.all("button"),i=e.keyCode!==37?1:-1,s=r.indexOf(t),o;s<0&&(s=0),s+=i,s<0?s=r.size()-1:s>=r.size()&&(s=0),o=r.item(s),this._setGroupTabFocus(n,o),o.focus()},_setGroupTabFocus:function(e,t){var n=e.generateID();typeof this._groupFocus[n]!="undefined"&&this._groupFocus[n].setAttribute("tabindex","-1"),this._groupFocus[n]=t,t.setAttribute("tabindex",0),e.setAttribute("aria-activedescendant",t.generateID())},_selectLibraryItem:function(e){var t=e.currentTarget.getAttribute("data-tex"),n,r,i,s=0;e.preventDefault(),this._setGroupTabFocus(e.currentTarget.get("parentNode"),e.currentTarget),i=e.currentTarget.ancestor(".atto_form").one("textarea"),n=i.get("value"),r=n.substring(0,this._lastCursorPos),r.charAt(r.length-1)!==" "&&(r+=" "),r+=t,s=r.length,n.charAt(this._lastCursorPos)!==" "&&(r+=" "),r+=n.substring(this._lastCursorPos,n.length),i.set("value",r),i.focus();var o=i.getDOMNode();if(typeof o.selectionStart=="number")o.selectionStart=o.selectionEnd=s;else if(typeof o.createTextRange!="undefined"){var u=o.createTextRange();u.moveToPoint(s),u.select()}this._updatePreview(!1)},_getLibraryContent:function(){var t=e.Handlebars.compile(u.LIBRARY),r=this.get("library"),s="";e.Handlebars.registerHelper("split",function(e,t,n){var r,i,s;if(typeof e=="undefined"||typeof t=="undefined")return"";s="",r=t.trim().split(e);while(r.length>0)i=r.shift().trim(),s+=n.fn(i);return s}),s=t({elementid:this.get("host").get("elementid"),component:n,library:r,CSS:i,DELIMITERS:o});var a=M.cfg.wwwroot+"/lib/editor/atto/plugins/equation/ajax.php",f={sesskey:M.cfg.sesskey,contextid:this.get("contextid"),action:"filtertext",text:s};return preview=e.io(a,{sync:!0,data:f,method:"POST"}),preview.status===200&&(s=preview.responseText),s}},{ATTRS:{texfilteractive:{value:!1},contextid:{value:null},library:{value:{}},texdocsurl:{value:null}}})},"@VERSION@",{requires:["moodle-editor_atto-plugin","moodle-core-event","io","event-valuechange","tabview","array-extras"]});
+YUI.add("moodle-atto_equation-button",function(e,t){var n="atto_equation",r="atto_equation",i={EQUATION_TEXT:"atto_equation_equation",EQUATION_PREVIEW:"atto_equation_preview",SUBMIT:"atto_equation_submit",LIBRARY:"atto_equation_library",LIBRARY_GROUPS:"atto_equation_groups",LIBRARY_GROUP_PREFIX:"atto_equation_group"},s={LIBRARY:"."+i.LIBRARY,LIBRARY_GROUP:"."+i.LIBRARY_GROUPS+" > div > div",EQUATION_TEXT:"."+i.EQUATION_TEXT,EQUATION_PREVIEW:"."+i.EQUATION_PREVIEW,SUBMIT:"."+i.SUBMIT,LIBRARY_BUTTON:"."+i.LIBRARY+" button"},o={START:"\\(",END:"\\)"},u={FORM:'<form class="atto_form">{{{library}}}<label for="{{elementid}}_{{CSS.EQUATION_TEXT}}">{{{get_string "editequation" component texdocsurl}}}</label><textarea class="fullwidth {{CSS.EQUATION_TEXT}}" id="{{elementid}}_{{CSS.EQUATION_TEXT}}" rows="8"></textarea><br/><label for="{{elementid}}_{{CSS.EQUATION_PREVIEW}}">{{get_string "preview" component}}</label><div describedby="{{elementid}}_cursorinfo" class="well well-small fullwidth {{CSS.EQUATION_PREVIEW}}" id="{{elementid}}_{{CSS.EQUATION_PREVIEW}}"></div><div id="{{elementid}}_cursorinfo">{{get_string "cursorinfo" component}}</div><div class="mdl-align"><br/><button class="{{CSS.SUBMIT}}">{{get_string "saveequation" component}}</button></div></form>',LIBRARY:'<div class="{{CSS.LIBRARY}}"><ul>{{#each library}}<li><a href="#{{../elementid}}_{{../CSS.LIBRARY_GROUP_PREFIX}}_{{@key}}">{{get_string groupname ../component}}</a></li>{{/each}}</ul><div class="{{CSS.LIBRARY_GROUPS}}">{{#each library}}<div id="{{../elementid}}_{{../CSS.LIBRARY_GROUP_PREFIX}}_{{@key}}"><div role="toolbar">{{#split "\n" elements}}<button tabindex="-1" data-tex="{{this}}" aria-label="{{this}}" title="{{this}}">{{../../DELIMITERS.START}}{{this}}{{../../DELIMITERS.END}}</button>{{/split}}</div></div>{{/each}}</div></div>'};e.namespace("M.atto_equation").Button=e.Base.create("button",e.M.editor_atto.EditorPlugin,[],{_currentSelection:null,_lastCursorPos:0,_content:null,_sourceEquation:null,_groupFocus:null,_equationPatterns:[/\$\$([\S\s]+?)\$\$/,/\\\(([\S\s]+?)\\\)/,/\\\[([\S\s]+?)\\\]/,/\[tex\]([\S\s]+?)\[\/tex\]/],initializer:function(){this._groupFocus={},this.get("texfilteractive")&&(this.addButton({icon:"e/math",callback:this._displayDialogue}),this.get("host").on("atto:selectionchanged",function(){this._resolveEquation()?this.highlightButtons():this.unHighlightButtons()},this),this.editor.all("tex").each(function(t){var n=e.Node.create("<span>"+o.START+" "+t.get("text")+" "+o.END+"</span>");t.replace(n)}))},_displayDialogue:function(){this._currentSelection=this.get("host").getSelection();if(this._currentSelection===!1)return;var t=this._resolveEquation(),r=this.getDialogue({headerContent:M.util.get_string("pluginname",n),focusAfterHide:!0,width:600,focusOnShowSelector:s.EQUATION_TEXT}),i=this._getDialogueContent();r.set("bodyContent",i);var o=i.one(s.LIBRARY),u=new e.TabView({srcNode:o});u.render(),r.show(),e.fire(M.core.event.FILTER_CONTENT_UPDATED,{nodes:new e.NodeList(r.get("boundingBox"))}),t&&i.one(s.EQUATION_TEXT).set("text",t),this._updatePreview(!1)},_resolveEquation:function(){var t=this.get("host").getSelectionParentNode(),n=this.get("host").getSelection(),r,i=!1;return this.get("host").isActive()?t?!n||n.length===0?!1:(this.sourceEquation=null,n=n[0],r=e.one(t).get("text"),e.Array.find(this._equationPatterns,function(t){var s=r.match(new RegExp(t.source,"g"));if(s&&s.length)return e.Array.find(s,function(e){var s=0;while(r.indexOf(e,s)!==-1){var o=r.indexOf(e,s),u=o+e.length,a=n.startOffset>=o&&n.startOffset<u,f=n.endOffset<=u&&n.endOffset>o;if(a&&f){var l=e.match(t);if(l&&l.length){var c=r.indexOf(l[1],o),h=c+l[1].length;return i=l[1],this.sourceEquation={startOuterPosition:o,endOuterPosition:u,outerMatch:e,startInnerPosition:c,endInnerPosition:h,innerMatch:l},!0}}s=u}},this)},this),i!==!1&&(i=i.trim()),i):!1:!1},_setEquation:function(t){var n,r,i,s,u;u=this.get("host"),t.preventDefault(),this.getDialogue({focusAfterHide:null}).hide(),n=t.currentTarget.ancestor(".atto_form").one("textarea"),s=n.get("value"),s!==""&&(u.setSelection(this._currentSelection),this.sourceEquation?(r=e.one(u.getSelectionParentNode()),i=r.get("text"),s=" "+s+" ",newText=i.slice(0,this.sourceEquation.startInnerPosition)+s+i.slice(this.sourceEquation.endInnerPosition),r.set("text",newText)):(s=o.START+" "+s+" "+o.END,u.insertContentAtFocusPoint(s)),this.markUpdated())},_throttle:function(e,t){var n=null;return function(){var r=this,i=arguments;clearTimeout(n),n=setTimeout(function(){e.apply(r,i)},t)}},_updatePreview:function(t){var n=this._content.one(s.EQUATION_TEXT),r=n.get("value"),i,u=n.get("selectionStart"),a="",f="\\Downarrow ",l,c;t&&t.preventDefault(),u||(u=0);while(r.charAt(u)==="\\"&&u>=0)u-=1;l=/[a-zA-Z\{\}]/;if(u!==0)while(l.test(r.charAt(u))&&u<r.length&&l.test(r.charAt(u-1)))u+=1;this._lastCursorPos=u,r=a+r.substring(0,u)+f+r.substring(u),r=o.START+" "+r+" "+o.END,i=M.cfg.wwwroot+"/lib/editor/atto/plugins/equation/ajax.php",c={sesskey:M.cfg.sesskey,contextid:this.get("contextid"),action:"filtertext",text:r},e.io(i,{context:this,data:c,timeout:500,on:{complete:this._loadPreview}})},_loadPreview:function(t,n){var r=this._content.one(s.EQUATION_PREVIEW);n.status===200&&(r.setHTML(n.responseText),e.fire(M.core.event.FILTER_CONTENT_UPDATED,{nodes:new e.NodeList(r)}))},_getDialogueContent:function(){var t=this._getLibraryContent(),r=this._throttle(this._updatePreview,500),o=e.Handlebars.compile(u.FORM);return this._content=e.Node.create(o({elementid:this.get("host").get("elementid"),component:n,library:t,texdocsurl:this.get("texdocsurl"),CSS:i})),this._content.all(s.LIBRARY_GROUP).each(function(e){this._setGroupTabFocus(e,e.one("button")),e.all("button a").setAttribute("tabindex","-1")},this),this._content.delegate("key",this._groupNavigation,"down:37,39",s.LIBRARY_BUTTON,this),this._content.one(s.SUBMIT).on("click",this._setEquation,this),this._content.one(s.EQUATION_TEXT).on("valuechange",r,this),this._content.one(s.EQUATION_TEXT
+).on("mouseup",r,this),this._content.one(s.EQUATION_TEXT).on("keyup",r,this),this._content.delegate("click",this._selectLibraryItem,s.LIBRARY_BUTTON,this),this._content},_groupNavigation:function(e){e.preventDefault();var t=e.currentTarget,n=t.get("parentNode"),r=n.all("button"),i=e.keyCode!==37?1:-1,s=r.indexOf(t),o;s<0&&(s=0),s+=i,s<0?s=r.size()-1:s>=r.size()&&(s=0),o=r.item(s),this._setGroupTabFocus(n,o),o.focus()},_setGroupTabFocus:function(e,t){var n=e.generateID();typeof this._groupFocus[n]!="undefined"&&this._groupFocus[n].setAttribute("tabindex","-1"),this._groupFocus[n]=t,t.setAttribute("tabindex",0),e.setAttribute("aria-activedescendant",t.generateID())},_selectLibraryItem:function(e){var t=e.currentTarget.getAttribute("data-tex"),n,r,i,s=0;e.preventDefault(),this._setGroupTabFocus(e.currentTarget.get("parentNode"),e.currentTarget),i=e.currentTarget.ancestor(".atto_form").one("textarea"),n=i.get("value"),r=n.substring(0,this._lastCursorPos),r.charAt(r.length-1)!==" "&&(r+=" "),r+=t,s=r.length,n.charAt(this._lastCursorPos)!==" "&&(r+=" "),r+=n.substring(this._lastCursorPos,n.length),i.set("value",r),i.focus();var o=i.getDOMNode();if(typeof o.selectionStart=="number")o.selectionStart=o.selectionEnd=s;else if(typeof o.createTextRange!="undefined"){var u=o.createTextRange();u.moveToPoint(s),u.select()}this._updatePreview(!1)},_getLibraryContent:function(){var t=e.Handlebars.compile(u.LIBRARY),r=this.get("library"),s="";e.Handlebars.registerHelper("split",function(e,t,n){var r,i,s;if(typeof e=="undefined"||typeof t=="undefined")return"";s="",r=t.trim().split(e);while(r.length>0)i=r.shift().trim(),s+=n.fn(i);return s}),s=t({elementid:this.get("host").get("elementid"),component:n,library:r,CSS:i,DELIMITERS:o});var a=M.cfg.wwwroot+"/lib/editor/atto/plugins/equation/ajax.php",f={sesskey:M.cfg.sesskey,contextid:this.get("contextid"),action:"filtertext",text:s};return preview=e.io(a,{sync:!0,data:f,method:"POST"}),preview.status===200&&(s=preview.responseText),s}},{ATTRS:{texfilteractive:{value:!1},contextid:{value:null},library:{value:{}},texdocsurl:{value:null}}})},"@VERSION@",{requires:["moodle-editor_atto-plugin","moodle-core-event","io","event-valuechange","tabview","array-extras"]});
diff --git a/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button.js b/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button.js
index b4429bce564..26334a11d2f 100644
--- a/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button.js
+++ b/lib/editor/atto/plugins/equation/yui/build/moodle-atto_equation-button/moodle-atto_equation-button.js
@@ -423,7 +423,6 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
         var textarea = this._content.one(SELECTORS.EQUATION_TEXT),
             equation = textarea.get('value'),
             url,
-            preview,
             currentPos = textarea.get('selectionStart'),
             prefix = '',
             cursorLatex = '\\Downarrow ',
@@ -455,7 +454,6 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
         this._lastCursorPos = currentPos;
         equation = prefix + equation.substring(0, currentPos) + cursorLatex + equation.substring(currentPos);
 
-        var previewNode = this._content.one(SELECTORS.EQUATION_PREVIEW);
         equation = DELIMITERS.START + ' ' + equation + ' ' + DELIMITERS.END;
         // Make an ajax request to the filter.
         url = M.cfg.wwwroot + '/lib/editor/atto/plugins/equation/ajax.php';
@@ -466,13 +464,30 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
             text: equation
         };
 
-        preview = Y.io(url, {
-            sync: true,
-            data: params
+        Y.io(url, {
+            context: this,
+            data: params,
+            timeout: 500,
+            on: {
+                complete: this._loadPreview
+            }
         });
+    },
+
+    /**
+     * Load returned preview text into preview
+     *
+     * @param {String} id
+     * @param {EventFacade} e
+     * @method _loadPreview
+     * @private
+     */
+    _loadPreview: function(id, preview) {
+        var previewNode = this._content.one(SELECTORS.EQUATION_PREVIEW);
 
         if (preview.status === 200) {
             previewNode.setHTML(preview.responseText);
+
             Y.fire(M.core.event.FILTER_CONTENT_UPDATED, {nodes: (new Y.NodeList(previewNode))});
         }
     },
@@ -487,6 +502,7 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
      */
     _getDialogueContent: function() {
         var library = this._getLibraryContent(),
+            throttledUpdate = this._throttle(this._updatePreview, 500),
             template = Y.Handlebars.compile(TEMPLATES.FORM);
 
         this._content = Y.Node.create(template({
@@ -509,9 +525,9 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
         this._content.delegate('key', this._groupNavigation, 'down:37,39', SELECTORS.LIBRARY_BUTTON, this);
 
         this._content.one(SELECTORS.SUBMIT).on('click', this._setEquation, this);
-        this._content.one(SELECTORS.EQUATION_TEXT).on('valuechange', this._throttle(this._updatePreview, 500), this);
-        this._content.one(SELECTORS.EQUATION_TEXT).on('mouseup', this._throttle(this._updatePreview, 500), this);
-        this._content.one(SELECTORS.EQUATION_TEXT).on('keyup', this._throttle(this._updatePreview, 500), this);
+        this._content.one(SELECTORS.EQUATION_TEXT).on('valuechange', throttledUpdate, this);
+        this._content.one(SELECTORS.EQUATION_TEXT).on('mouseup', throttledUpdate, this);
+        this._content.one(SELECTORS.EQUATION_TEXT).on('keyup', throttledUpdate, this);
         this._content.delegate('click', this._selectLibraryItem, SELECTORS.LIBRARY_BUTTON, this);
 
         return this._content;
diff --git a/lib/editor/atto/plugins/equation/yui/src/button/js/button.js b/lib/editor/atto/plugins/equation/yui/src/button/js/button.js
index 11244960c4a..3ad02e955ed 100644
--- a/lib/editor/atto/plugins/equation/yui/src/button/js/button.js
+++ b/lib/editor/atto/plugins/equation/yui/src/button/js/button.js
@@ -421,7 +421,6 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
         var textarea = this._content.one(SELECTORS.EQUATION_TEXT),
             equation = textarea.get('value'),
             url,
-            preview,
             currentPos = textarea.get('selectionStart'),
             prefix = '',
             cursorLatex = '\\Downarrow ',
@@ -453,7 +452,6 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
         this._lastCursorPos = currentPos;
         equation = prefix + equation.substring(0, currentPos) + cursorLatex + equation.substring(currentPos);
 
-        var previewNode = this._content.one(SELECTORS.EQUATION_PREVIEW);
         equation = DELIMITERS.START + ' ' + equation + ' ' + DELIMITERS.END;
         // Make an ajax request to the filter.
         url = M.cfg.wwwroot + '/lib/editor/atto/plugins/equation/ajax.php';
@@ -464,13 +462,30 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
             text: equation
         };
 
-        preview = Y.io(url, {
-            sync: true,
-            data: params
+        Y.io(url, {
+            context: this,
+            data: params,
+            timeout: 500,
+            on: {
+                complete: this._loadPreview
+            }
         });
+    },
+
+    /**
+     * Load returned preview text into preview
+     *
+     * @param {String} id
+     * @param {EventFacade} e
+     * @method _loadPreview
+     * @private
+     */
+    _loadPreview: function(id, preview) {
+        var previewNode = this._content.one(SELECTORS.EQUATION_PREVIEW);
 
         if (preview.status === 200) {
             previewNode.setHTML(preview.responseText);
+
             Y.fire(M.core.event.FILTER_CONTENT_UPDATED, {nodes: (new Y.NodeList(previewNode))});
         }
     },
@@ -485,6 +500,7 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
      */
     _getDialogueContent: function() {
         var library = this._getLibraryContent(),
+            throttledUpdate = this._throttle(this._updatePreview, 500),
             template = Y.Handlebars.compile(TEMPLATES.FORM);
 
         this._content = Y.Node.create(template({
@@ -507,9 +523,9 @@ Y.namespace('M.atto_equation').Button = Y.Base.create('button', Y.M.editor_atto.
         this._content.delegate('key', this._groupNavigation, 'down:37,39', SELECTORS.LIBRARY_BUTTON, this);
 
         this._content.one(SELECTORS.SUBMIT).on('click', this._setEquation, this);
-        this._content.one(SELECTORS.EQUATION_TEXT).on('valuechange', this._throttle(this._updatePreview, 500), this);
-        this._content.one(SELECTORS.EQUATION_TEXT).on('mouseup', this._throttle(this._updatePreview, 500), this);
-        this._content.one(SELECTORS.EQUATION_TEXT).on('keyup', this._throttle(this._updatePreview, 500), this);
+        this._content.one(SELECTORS.EQUATION_TEXT).on('valuechange', throttledUpdate, this);
+        this._content.one(SELECTORS.EQUATION_TEXT).on('mouseup', throttledUpdate, this);
+        this._content.one(SELECTORS.EQUATION_TEXT).on('keyup', throttledUpdate, this);
         this._content.delegate('click', this._selectLibraryItem, SELECTORS.LIBRARY_BUTTON, this);
 
         return this._content;