diff --git a/static/plugin_dbui/src/grid/button/ExpertMenu.js b/static/plugin_dbui/src/grid/button/ExpertMenu.js
index 9e50620de19e730feeeef2a31252ea24d82d6598..f2d860399e40c8c9d6d985c108a0254d6f2d02c5 100644
--- a/static/plugin_dbui/src/grid/button/ExpertMenu.js
+++ b/static/plugin_dbui/src/grid/button/ExpertMenu.js
@@ -56,9 +56,37 @@ Ext.define('App.grid.button.ExpertMenu', {
         // initialise the base class
         this.callParent(arguments);
 
+        // process checkItem event
         if (pGridMathJax) {
             this.buttonMathJax = this.menu.getComponent('buttonMathJax');
-            this.buttonMathJax.on('checkchange', pGridMathJax.onCheckItemChange, pGridMathJax);
+            this.buttonMathJax.on('checkchange', this.onCheckItemChange, pGridMathJax);
+        }
+    },
+
+    /**
+     * Activate /deactivate the MathJax processing.
+     * Private handler used by the expert menu.
+     *
+     * @param {Ext.menu.CheckItem} menuItem
+     * @param {Boolean} checked
+     * @param {Object} eOpts
+     *
+     */
+    onCheckItemChange: function (menuItem, checked, eOpts) {
+
+        "use strict";
+
+        var pGridMathJax = this;
+
+        pGridMathJax.activated = checked;
+
+        // process equation
+        if (checked) {
+            pGridMathJax.onProcessMath();
+
+        // refresh the grid
+        } else {
+            pGridMathJax.getCmp().getView().refresh();
         }
     },
 
diff --git a/static/plugin_dbui/src/grid/plugin/MathJax.js b/static/plugin_dbui/src/grid/plugin/MathJax.js
index 5615c3275a35b2cfb4d047a1659d42544ce8823c..99863834e0e2f90e50ab57d7c5d52aba6349fc89 100644
--- a/static/plugin_dbui/src/grid/plugin/MathJax.js
+++ b/static/plugin_dbui/src/grid/plugin/MathJax.js
@@ -48,29 +48,6 @@ Ext.define('App.grid.plugin.MathJax', {
         this.getCmp().getView().un('refresh', this.onProcessMath, this);
     },
 
-    /**
-     * Activate /deactivate the MathJax processing.
-     * Private handler used by the expert menu.
-     *
-     * @param {Ext.menu.CheckItem} menuItem
-     * @param {Boolean} checked
-     * @param {Object} eOpts
-     *
-     */
-    onCheckItemChange: function (menuItem, checked, eOpts) {
-
-        "use strict";
-
-        this.activated = checked;
-
-        if (this.activated) {
-            this.onProcessMath();
-
-        } else {
-            this.getCmp().getView().refresh();
-        }
-    },
-
     /**
      * Process maths objects
      *