diff --git a/ubb-la/gui.c b/ubb-la/gui.c
index dc6e2a4..0743e97 100644
--- a/ubb-la/gui.c
+++ b/ubb-la/gui.c
@@ -177,6 +177,7 @@ static void show_map(int skip, int nibbles, int s0, int s1)
 	int w = nibbles-skip;
 	int m = (nibbles+skip) >> 1;
 	int scale = 0;
+	int x0, x1;
 
 	while (w >= XWIDTH/2) {
 		w >>= 1;
@@ -184,8 +185,9 @@ static void show_map(int skip, int nibbles, int s0, int s1)
 	}
 	boxColor(surf, XCENTER-(w >> 1), MAP_BUF_Y0,
 	    XCENTER+(w >> 1), MAP_BUF_Y1, MAP_BUF_RGBA);
-	rectangleColor(surf, (s0-m+(XCENTER << scale)) >> scale, MAP_VIEW_Y0,
-	    (s1-m+(XCENTER << scale)) >> scale, MAP_VIEW_Y1, MAP_VIEW_RGBA);
+	x0 = (s0-m+(XCENTER << scale)) >> scale;
+	x1 = x0+((s1-s0) >> scale);
+	rectangleColor(surf, x0, MAP_VIEW_Y0, x1, MAP_VIEW_Y1, MAP_VIEW_RGBA);
 }