diff --git a/include/validate.cpp b/include/validate.cpp
index 02b1f4dc6..c9f7848fa 100755
--- a/include/validate.cpp
+++ b/include/validate.cpp
@@ -278,7 +278,7 @@ HIDDEN bool _xt_cf_val(TEdit_field& f, KEY key)
 {
   if (f.mask().query_mode()) return TRUE;
   
-  const TString16 cf(f.get()); 
+  TString16 cf(f.get()); 
   if (cf.empty()) return f.error_box("Codice fiscale obbligatorio");
   
   if (!_cf_val(f, key)) return FALSE;