The source code

    /**
    * @class Ext.EventManager
    */
    Ext.apply(Ext.EventManager, function(){
       var resizeEvent,
           resizeTask,
           textEvent,
           textSize,
           D = Ext.lib.Dom,
           propRe = /^(?:scope|delay|buffer|single|stopEvent|preventDefault|stopPropagation|normalized|args|delegate)$/,
           unload = Ext.EventManager._unload,
           curWidth = 0,
           curHeight = 0,
           // note 1: IE fires ONLY the keydown event on specialkey autorepeat
           // note 2: Safari < 3.1, Gecko (Mac/Linux) & Opera fire only the keypress event on specialkey autorepeat
           // (research done by @Jan Wolter at http://unixpapa.com/js/key.html)
           useKeydown = Ext.isWebKit ?
                       Ext.num(navigator.userAgent.match(/AppleWebKit\/(\d+)/)[1]) >= 525 :
                       !((Ext.isGecko && !Ext.isWindows) || Ext.isOpera);

       return {
           _unload: function(){
               Ext.EventManager.un(window, "resize", this.fireWindowResize, this);
               unload.call(Ext.EventManager);
           },

           // private
           doResizeEvent: function(){
               var h = D.getViewHeight(),
                   w = D.getViewWidth();

                //whacky problem in IE where the resize event will fire even though the w/h are the same.
                if(curHeight != h || curWidth != w){
                   resizeEvent.fire(curWidth = w, curHeight = h);
                }
           },

           /**
            * Adds a listener to be notified when the browser window is resized and provides resize event buffering (100 milliseconds),
            * passes new viewport width and height to handlers.
            * @param {Function} fn      The handler function the window resize event invokes.
            * @param {Object}   scope   The scope (<code>this</code> reference) in which the handler function executes. Defaults to the browser window.
            * @param {boolean}  options Options object as passed to {@link Ext.Element#addListener}
            */
           onWindowResize : function(fn, scope, options){
               if(!resizeEvent){
                   resizeEvent = new Ext.util.Event();
                   resizeTask = new Ext.util.DelayedTask(this.doResizeEvent);
                   Ext.EventManager.on(window, "resize", this.fireWindowResize, this);
               }
               resizeEvent.addListener(fn, scope, options);
           },

           // exposed only to allow manual firing
           fireWindowResize : function(){
               if(resizeEvent){
                   resizeTask.delay(100);
               }
           },

           /**
            * Adds a listener to be notified when the user changes the active text size. Handler gets called with 2 params, the old size and the new size.
            * @param {Function} fn      The function the event invokes.
            * @param {Object}   scope   The scope (<code>this</code> reference) in which the handler function executes. Defaults to the browser window.
            * @param {boolean}  options Options object as passed to {@link Ext.Element#addListener}
            */
           onTextResize : function(fn, scope, options){
               if(!textEvent){
                   textEvent = new Ext.util.Event();
                   var textEl = new Ext.Element(document.createElement('div'));
                   textEl.dom.className = 'x-text-resize';
                   textEl.dom.innerHTML = 'X';
                   textEl.appendTo(document.body);
                   textSize = textEl.dom.offsetHeight;
                   setInterval(function(){
                       if(textEl.dom.offsetHeight != textSize){
                           textEvent.fire(textSize, textSize = textEl.dom.offsetHeight);
                       }
                   }, this.textResizeInterval);
               }
               textEvent.addListener(fn, scope, options);
           },

           /**
            * Removes the passed window resize listener.
            * @param {Function} fn        The method the event invokes
            * @param {Object}   scope    The scope of handler
            */
           removeResizeListener : function(fn, scope){
               if(resizeEvent){
                   resizeEvent.removeListener(fn, scope);
               }
           },

           // private
           fireResize : function(){
               if(resizeEvent){
                   resizeEvent.fire(D.getViewWidth(), D.getViewHeight());
               }
           },

            /**
            * The frequency, in milliseconds, to check for text resize events (defaults to 50)
            */
           textResizeInterval : 50,

           /**
            * Url used for onDocumentReady with using SSL (defaults to Ext.SSL_SECURE_URL)
            */
           ieDeferSrc : false,

           // protected, short accessor for useKeydown
           getKeyEvent : function(){
               return useKeydown ? 'keydown' : 'keypress';
           },

           // protected for use inside the framework
           // detects whether we should use keydown or keypress based on the browser.
           useKeydown: useKeydown
       };
    }());

    Ext.EventManager.on = Ext.EventManager.addListener;

    Ext.apply(Ext.EventObjectImpl.prototype, {
       /** Key constant @type Number */
       BACKSPACE: 8,
       /** Key constant @type Number */
       TAB: 9,
       /** Key constant @type Number */
       NUM_CENTER: 12,
       /** Key constant @type Number */
       ENTER: 13,
       /** Key constant @type Number */
       RETURN: 13,
       /** Key constant @type Number */
       SHIFT: 16,
       /** Key constant @type Number */
       CTRL: 17,
       CONTROL : 17, // legacy
       /** Key constant @type Number */
       ALT: 18,
       /** Key constant @type Number */
       PAUSE: 19,
       /** Key constant @type Number */
       CAPS_LOCK: 20,
       /** Key constant @type Number */
       ESC: 27,
       /** Key constant @type Number */
       SPACE: 32,
       /** Key constant @type Number */
       PAGE_UP: 33,
       PAGEUP : 33, // legacy
       /** Key constant @type Number */
       PAGE_DOWN: 34,
       PAGEDOWN : 34, // legacy
       /** Key constant @type Number */
       END: 35,
       /** Key constant @type Number */
       HOME: 36,
       /** Key constant @type Number */
       LEFT: 37,
       /** Key constant @type Number */
       UP: 38,
       /** Key constant @type Number */
       RIGHT: 39,
       /** Key constant @type Number */
       DOWN: 40,
       /** Key constant @type Number */
       PRINT_SCREEN: 44,
       /** Key constant @type Number */
       INSERT: 45,
       /** Key constant @type Number */
       DELETE: 46,
       /** Key constant @type Number */
       ZERO: 48,
       /** Key constant @type Number */
       ONE: 49,
       /** Key constant @type Number */
       TWO: 50,
       /** Key constant @type Number */
       THREE: 51,
       /** Key constant @type Number */
       FOUR: 52,
       /** Key constant @type Number */
       FIVE: 53,
       /** Key constant @type Number */
       SIX: 54,
       /** Key constant @type Number */
       SEVEN: 55,
       /** Key constant @type Number */
       EIGHT: 56,
       /** Key constant @type Number */
       NINE: 57,
       /** Key constant @type Number */
       A: 65,
       /** Key constant @type Number */
       B: 66,
       /** Key constant @type Number */
       C: 67,
       /** Key constant @type Number */
       D: 68,
       /** Key constant @type Number */
       E: 69,
       /** Key constant @type Number */
       F: 70,
       /** Key constant @type Number */
       G: 71,
       /** Key constant @type Number */
       H: 72,
       /** Key constant @type Number */
       I: 73,
       /** Key constant @type Number */
       J: 74,
       /** Key constant @type Number */
       K: 75,
       /** Key constant @type Number */
       L: 76,
       /** Key constant @type Number */
       M: 77,
       /** Key constant @type Number */
       N: 78,
       /** Key constant @type Number */
       O: 79,
       /** Key constant @type Number */
       P: 80,
       /** Key constant @type Number */
       Q: 81,
       /** Key constant @type Number */
       R: 82,
       /** Key constant @type Number */
       S: 83,
       /** Key constant @type Number */
       T: 84,
       /** Key constant @type Number */
       U: 85,
       /** Key constant @type Number */
       V: 86,
       /** Key constant @type Number */
       W: 87,
       /** Key constant @type Number */
       X: 88,
       /** Key constant @type Number */
       Y: 89,
       /** Key constant @type Number */
       Z: 90,
       /** Key constant @type Number */
       CONTEXT_MENU: 93,
       /** Key constant @type Number */
       NUM_ZERO: 96,
       /** Key constant @type Number */
       NUM_ONE: 97,
       /** Key constant @type Number */
       NUM_TWO: 98,
       /** Key constant @type Number */
       NUM_THREE: 99,
       /** Key constant @type Number */
       NUM_FOUR: 100,
       /** Key constant @type Number */
       NUM_FIVE: 101,
       /** Key constant @type Number */
       NUM_SIX: 102,
       /** Key constant @type Number */
       NUM_SEVEN: 103,
       /** Key constant @type Number */
       NUM_EIGHT: 104,
       /** Key constant @type Number */
       NUM_NINE: 105,
       /** Key constant @type Number */
       NUM_MULTIPLY: 106,
       /** Key constant @type Number */
       NUM_PLUS: 107,
       /** Key constant @type Number */
       NUM_MINUS: 109,
       /** Key constant @type Number */
       NUM_PERIOD: 110,
       /** Key constant @type Number */
       NUM_DIVISION: 111,
       /** Key constant @type Number */
       F1: 112,
       /** Key constant @type Number */
       F2: 113,
       /** Key constant @type Number */
       F3: 114,
       /** Key constant @type Number */
       F4: 115,
       /** Key constant @type Number */
       F5: 116,
       /** Key constant @type Number */
       F6: 117,
       /** Key constant @type Number */
       F7: 118,
       /** Key constant @type Number */
       F8: 119,
       /** Key constant @type Number */
       F9: 120,
       /** Key constant @type Number */
       F10: 121,
       /** Key constant @type Number */
       F11: 122,
       /** Key constant @type Number */
       F12: 123,

       /** @private */
       isNavKeyPress : function(){
           var me = this,
               k = this.normalizeKey(me.keyCode);
           return (k >= 33 && k <= 40) ||  // Page Up/Down, End, Home, Left, Up, Right, Down
           k == me.RETURN ||
           k == me.TAB ||
           k == me.ESC;
       },

       isSpecialKey : function(){
           var k = this.normalizeKey(this.keyCode);
           return (this.type == 'keypress' && this.ctrlKey) ||
           this.isNavKeyPress() ||
           (k == this.BACKSPACE) || // Backspace
           (k >= 16 && k <= 20) || // Shift, Ctrl, Alt, Pause, Caps Lock
           (k >= 44 && k <= 46);   // Print Screen, Insert, Delete
       },

       getPoint : function(){
           return new Ext.lib.Point(this.xy[0], this.xy[1]);
       },

       /**
        * Returns true if the control, meta, shift or alt key was pressed during this event.
        * @return {Boolean}
        */
       hasModifier : function(){
           return ((this.ctrlKey || this.altKey) || this.shiftKey);
       }
    });