bookmark-menu-popup-paned-menu is a compiled Lisp function in `bookmark.el'.

(bookmark-menu-popup-paned-menu EVENT NAME ENTRIES)

Pop up multi-paned menu at EVENT, return string chosen from ENTRIES.
That is, ENTRIES is a list of strings which appear as the choices
in the menu.
The number of panes depends on the number of entries.
The visible entries are truncated to `bookmark-menu-length', but the
strings returned are not.