diff --git a/src/ui.c b/src/ui.c
index a734e7b..fc58920 100644
--- a/src/ui.c
+++ b/src/ui.c
@@ -1911,7 +1911,7 @@
 #endif
 
 #if defined(FEAT_CLIPBOARD) || defined(FEAT_GUI) || defined(FEAT_RIGHTLEFT) \
-	|| defined(PROTO)
+	|| defined(FEAT_MBYTE) || defined(PROTO)
 /*
  * Check bounds for column number
  */