onDestroy method of features isn't being called

[jacobweber]

The onDestroy methods of the Feature classes aren't being called. Feature.initFeatures uses a 'beforedestroy' event to attach the listener, but I don't think that event is ever fired.

In addition, the onDestroy method of Sorter looks like it would break if it were ever called; it uses things like grid.el instead of grid.element.

[jacobweber]

You can fix it by adding this to List.js:

    destroy: function() {
        this.fireEvent('beforedestroy', this);
        this.callParent(arguments);
    }

And changing Sorter.js like this:

    onDestroy: function() {
        var me     = this,
            grid   = me.getGrid(),
            header = grid.getHeader(),
            el     = header.element;