(imin 0) imax lw rw)
(while (< imin (length LilyPond-menu-keywords))
(setq imax (- (min (+ imin w) (length LilyPond-menu-keywords)) 1))
(setq lw (nth imin LilyPond-menu-keywords))
(setq rw (nth imax LilyPond-menu-keywords))
(imin 0) imax lw rw)
(while (< imin (length LilyPond-menu-keywords))
(setq imax (- (min (+ imin w) (length LilyPond-menu-keywords)) 1))
(setq lw (nth imin LilyPond-menu-keywords))
(setq rw (nth imax LilyPond-menu-keywords))