Ext.GridCellSelectionModel = Ext.extend(Ext.AbstractStoreSelectionModel, {
    
/**
     * @cfg {Boolean} enableKeyNav
     * Turns on/off keyboard navigation within the grid. Defaults to true.
     */
    enableKeyNav: true,

    bindComponent: function(grid) {
        this.grid = grid;
        this.bind(grid.getStore());
        grid.on({
            cellmousedown: this.onCellMouseDown,
            scope: this
        });

        var view = grid.getView();
        view.on({
            refresh: this.refresh,
            rowupdated: this.onRowUpdated,
            beforerowremoved: this.clearSelections,
            beforerowsinserted: this.clearSelections,
            scope: this
        });

        if (this.enableKeyNav) {
            this.initKeyNav();
        }

        // handle before editing
    },

    initKeyNav: function() {
        var grid = this.grid;
        if (!grid.rendered) {
            this.grid.on('render', this.initKeyNav, this, {single: true});
            return;
        }

        var view = grid.view;
        // view.el has tabIndex -1 to allow for
        // keyboard events to be passed to it.
        this.keyNav = new Ext.util.KeyNav(view.el, {
            "up": this.onKeyUp,
            "down": this.onKeyDown,
            "pageDown": this.onKeyPageDown,
            "pageUp": this.onKeyPageUp,
            "home": this.onKeyHome,
            "end": this.onKeyEnd,
            scope: this
        });
        view.el.on(Ext.EventManager.getKeyEvent(), this.onKeyPress, this);
    }
});