Review

No High or Medium issues found.

The change is a minimal, correct fix. setup_filters() calls filter_accordions.html(html) (modular-list.js:645) which replaces the entire #list-filter-tabs DOM, destroying the cloned <template id="template-split-by-filter"> content and the button inside it. After that replacement, the original direct binding $('#split_by_current_filter_button').on('click', ...) is dead — the new button has no handler. Switching to $(document).on('click', '#split_by_current_filter_button', ...) delegates through the document, so the handler fires correctly after any DOM replacement.

Ready to merge.

@corsacca review ready.....

Thanks @kodinkat!