Function useClickOutside

frontend/src/react/components/ExprEditor.tsx:175–193

(
  refs: React.RefObject<HTMLElement | null>[],
  open: boolean,
  onClose: () => void
)

// ============================================================

function useClickOutside(
  refs: React.RefObject<HTMLElement | null>[],
  open: boolean,
  onClose: () => void
) {
  const refsRef = useRef(refs);
  refsRef.current = refs;
  useEffect(() => {
    if (!open) return;
    const handler = (e: MouseEvent) => {
      const target = e.target as Node;
      if (refsRef.current.every((r) => !r.current?.contains(target))) {
        onClose();
      }
    };
    document.addEventListener("mousedown", handler);
    return () => document.removeEventListener("mousedown", handler);
  }, [open, onClose]);
}

function PortaledDropdown({
  anchorRef,