diff --git a/include/validate.cpp b/include/validate.cpp
index fcc259474..3e7537989 100755
--- a/include/validate.cpp
+++ b/include/validate.cpp
@@ -559,8 +559,20 @@ HIDDEN bool _onereq_val(TEdit_field& f, KEY k)
   return FALSE;
 }
 
+HIDDEN bool _chkfld_val(TEdit_field& f, KEY k)
+{
+  if (f.to_check(k))
+  {
+    const int fldid = atoi(get_val_param(0));
+    TMask_field & chkfld = f.mask().field(fldid);
+    
+    chkfld.set(f.get());
+    return chkfld.check();
+  }
+  return TRUE;
+}
 
-#define MAX_FUNC 17
+#define MAX_FUNC 18
 
 HIDDEN VAL_FUNC _global_val_func[MAX_FUNC] = 
 {
@@ -580,7 +592,8 @@ HIDDEN VAL_FUNC _global_val_func[MAX_FUNC] =
   _autoexit_val,
   _numcalc_val,
   _strcalc_val,
-  _onereq_val
+  _onereq_val,
+  _chkfld_val
   };
 
 bool validate(int fn, TEdit_field& f, KEY k, const TArray& parms)