eval in php file triggering a virus alert

I just got an alert from my virus scanner that the file in js/min/ called jquery-ui-dialog.php might have a virus.

I opened the file and it’a a base 64 eval

<?php
eval(gzinflate(base64_decode('.... I'm removing a ton of code here.....')));
?>

is this normal or do i have a virus in the plugin ?

https://wordpress.org/plugins/crayon-syntax-highlighter/