diff --git a/cde/programs/dthelp/parser/pass2/htag2/custom.c b/cde/programs/dthelp/parser/pass2/htag2/custom.c
index c4a0986b5..8fb442132 100644
--- a/cde/programs/dthelp/parser/pass2/htag2/custom.c
+++ b/cde/programs/dthelp/parser/pass2/htag2/custom.c
@@ -167,6 +167,7 @@ do  {
     {
 	mbyte[length++] = c;
 	mbyte[length]   = 0;
+	mblen(NULL, 0);
 	if (mblen(mbyte,length) != -1) break; /* hurray! */
 	if (length == MB_CUR_MAX)
         { /* reached max without a hit */