Adding quotes or links to widget text breaks output

If you add quotes " or e.g. an additional html-link within the textarea of a focus widget in Zerif Lite 1.8.2.1, saving the widget causes added slashes where it shouldn’t.

Example: href="something" becomes href=\"something\" and similar.

Reason is in update(..) of widgets in functions.php, line 651

$instance['text'] = wp_filter_post_kses($new_instance['text']);

As a workaround replace with this line:

$instance['text'] = stripslashes( wp_filter_post_kses($new_instance['text']) );

Thanks for the cool theme.

Some related discussion about a similar problem can be read in an old WP ticket…