MY FIX: Trying to get property of non-object avh-ec.widgets.php on line 479

I got this error:

[01-Aug-2017 07:58:13 UTC] PHP Notice: Trying to get property of non-object in /dir/to/path/wp-content/plugins/extended-categories-widget/4.2/class/avh-ec.widgets.php on line 479

My fix was to change this:

if ($category_group_id_none == $row->term_id) {
    $toDisplay = false;
} elseif ( ! (false == $selected_catgroups || array_key_exists($row->term_id, $selected_catgroups))) {
    $toDisplay = false;
} elseif ($special_page != 'none' && $this->getWidgetDoneCatGroup($sp_category_group_id)) {
    $toDisplay = false;
}

Into this:

if ( !isset($row->term_id) ) {
    $toDisplay = false;
} elseif ($category_group_id_none == $row->term_id) {
    $toDisplay = false;
} elseif ( ! (false == $selected_catgroups || array_key_exists($row->term_id, $selected_catgroups))) {
    $toDisplay = false;
} elseif ($special_page != 'none' && $this->getWidgetDoneCatGroup($sp_category_group_id)) {
    $toDisplay = false;
}