So, here we go.
In resources/widget.php change
var params = {
"containerID": "<?php echo $this->cmpId;?>",
"initialTab" : "<?php echo $initial_tab;?>",
"feedID" : <?php echo (!$feed_id) ? "false" : "'".$feed_id."'";?>,
"width" : "100%"
};
to
var params = {
"containerID": "<?php echo $this->cmpId;?>",
"initialTab" : "<?php echo $initial_tab;?>",
<?php if ( $feed_id ) { ?>
"feedID" : <?php echo $feed_id; ?>,
<?php } ?>
"width" : "100%"
};
In widget.php change
$title = esc_attr($instance['title']);
$feed_id = esc_attr($instance['feed_id']);
if(empty($initial_tab)) $feed_id = "";
$initial_tab = esc_attr($instance['initial_tab']);
if(empty($initial_tab)) $initial_tab = "everyone";
to
$title = esc_attr($instance['title']);
$feed_id = esc_attr($instance['feed_id']);
$initial_tab = esc_attr($instance['initial_tab']);
if(empty($initial_tab)) {
$initial_tab = "everyone";
$feed_id = "";
}