删除小部件时请注意

I'm trying to customize itheme's Exchange e-commerce plugin. I'd like to add a catalogue ability - removing add to cart and buy now buttons. Since in exchange those buttons are created using their 'superwidget', I thought that the easiest way to remove those buttons is by removing the superwidget. So i created a function:

if(!function_exists('exchange_catalogue')){
    function exchange_catalogue(){
        unregister_widget( 'IT_Exchange_Super_Widget' );
    }
}

add_filter( 'widgets_init', 'exchange_catalogue');

But I get:

Notice: Undefined index: IT_Exchange_Super_Widget in /wp-includes/widgets.php on line 1356

I checked if there is such registered widget:

$widgets = array_keys( $GLOBALS['wp_widget_factory']->widgets );
print '<pre>$widgets = ' . esc_html( var_export( $widgets, TRUE ) ) . '</pre>';

just added that to the function above, and the widget is there (listed)

$widgets = array (
...
 26 => 'IT_Exchange_Super_Widget',
)

So if it exists, and my function removes it, why am I getting this notice??

Oh, and I am aware that there is an option for this, but only if you buy their expansion for ~$200, that will add an add on...

EDIT:

I tried with this:

    if (isset( $GLOBALS['wp_widget_factory']->widgets['IT_Exchange_Super_Widget'] )) {
        unset( $GLOBALS['wp_widget_factory']->widgets['IT_Exchange_Super_Widget'] );
    }

And with

    if (isset( $GLOBALS['wp_widget_factory']->widgets['IT_Exchange_Super_Widget'] )) {
        unregister_widget( 'IT_Exchange_Super_Widget' );
    }

But still am getting the notice.

Found the answer! :D

I just put

if(!function_exists('exchange_catalogue')){
    function exchange_catalogue(){
       if (isset( $GLOBALS['wp_widget_factory'])) {
           $GLOBALS['wp_widget_factory']->widgets['IT_Exchange_Super_Widget'] = null;
       }
    }
}

This way the widget is set, but it's nothing. So it's not showing :D Simple fix if you want catalog ability for exchange shop :)