diff --git a/src/highlight.c b/src/highlight.c
index 8b1e832..31c3280 100644
--- a/src/highlight.c
+++ b/src/highlight.c
@@ -3814,6 +3814,7 @@
 		if (attr > HL_ALL)  // Combination with ':' is not allowed.
 		    return FAIL;
 
+		// Note: Keep this in sync with expand_set_highlight().
 		switch (*p)
 		{
 		    case 'b':	attr |= HL_BOLD;