Hi,
Thanks for your query. Please follow the below instruction's.
Go to below location
templates\shaper_qubic\index.php
Find out below code
$doc->addScriptdeclaration( "\nvar onePageUrl = '".JURI::base(true) . "';\n" );
And replace with this code
$doc->addScriptdeclaration( "\nvar onePageUrl = '".JURI::base(true) . "';\n" );
Add this class inside of Helix menu options > sidebar > Custom CSS Class > no-scroll
-Thanks