     #! x*n is the screen position of the thumb, and conversely
     #! for x/n. The '1 max' calls avoid division by zero.
     [ [ elevator-length ] [ thumb-dim ] bi - 1 max ]
-    [ slider-max* 1 max ]
+    [ slider-length* 1 max ]
     bi / ;
 
 : slider>screen ( m slider -- n ) slider-scale * ;

            [ <up-button> f track-add ]
            [ <down-button> f track-add ]
            [ drop <gadget> { 1 1 } >>dim f track-add ]
        } cleave ;
        swap >>orientation ;

: thumb-loc ( slider -- loc )
    [ slider-value ]
    [ slider-min - ]
    [ slider>screen elevator-padding + ] tri ;

: layout-thumb-loc ( thumb slider -- )
    [ thumb-loc ] [ orientation>> ] bi n*v
