diff --git a/src/screen.c b/src/screen.c
index f9a847d..a0e9fc9 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -4341,7 +4341,7 @@
 			  || (mb_utf8 && mb_c == 160)
 #endif
 			 ) && lcs_nbsp)
-			|| (c == ' ' && lcs_space && ptr <= line + trailcol)))
+			|| (c == ' ' && lcs_space && ptr - line <= trailcol)))
 	    {
 		c = (c == ' ') ? lcs_space : lcs_nbsp;
 		if (area_attr == 0 && search_attr == 0)