In memberlist_search.html forum_fn.js is included via INCLUDEJS, which should not be included there because its included in simple_footer.html already. If search is not opened via popup code is incorrect anyway because forum_fn.js is included in overall_footer.html.

In simple_footer.html forum_fn.js is included via < script > tag instead of INCLUDEJS

In simple_footer.html included scripts are added as

instead of {$SCRIPTS}, so included scripts do not work