bueno yo lohago de esta forma y esmas sencillo y facil de enterder
aki abres el system.def del la carpeta data y buscas esata linea
;-----------------------
;Character select screen background
[SelectBGdef]
;spr = graphics/selectbg.sff ;Filename of sprite data
[SelectBG 0] ;background
type = normal
spriteno = 100,7
layerno = 0
start = 0,0
tile = 1,1
[SelectBG 1] ;Dark box
type = normal
spriteno = 100,1
layerno = 0
start = 0, 166
delta = 0,0
tile = 1,0
trans = sub
window = 85,0, 235,239
velocity = -1, 0
[SelectBG 2.A] ;Title background
type = normal
spriteno = 102,0
layerno = 0
start = 0, 2
delta = 0,0
tile = 1,0
trans = sub
velocity = -1, 0
[SelectBG 2.B] ;Title background B
type = normal
spriteno = 102,1
layerno = 0
start = 0, 2
delta = 0,0
tile = 1,0
trans = add
velocity = -3, 0
[SelectBG 2.C] ;Title background C
type = normal
spriteno = 102,2
layerno = 0
start = 0, 2
delta = 0,0
tile = 1,0
trans = add
velocity = -6, 0
simplemente la borras "velocity" y hay se va a kear kieto y listo