diff --git a/src/u_synmemo.pas b/src/u_synmemo.pas
index caf502cc..d4db5b5c 100644
--- a/src/u_synmemo.pas
+++ b/src/u_synmemo.pas
@@ -2573,7 +2573,7 @@ begin
   if right then
     c := s[p.x]
   else
-    c := s[p.x-1];
+    c := s[min(p.x-1, s.length)];
   if not right then
   begin
     if c in w then