Fatal error into templating functions – page_template_dropdown not defined

Hi!

Looks like something wrong with templating functios:

Fatal error: Call to undefined function page_template_dropdown() in /site_path/wp-content/plugins/insert-pages/widget.php on line 101

Fatal error comes up not only into FE side,but also in to wp-admin side.

Some thing like this comes up – https://snag.gy/4KihOI.jpg / https://snag.gy/gMrOj6.jpg

As quickfix I solved this only by commeting out that function call into widgets.php 101 line – <?php page_template_dropdown( $instance['template'] ); ?>

https://wordpress.org/plugins/insert-pages/