diff --git a/include/maskfld.cpp b/include/maskfld.cpp
index c07c6ef4c..3976c4570 100755
--- a/include/maskfld.cpp
+++ b/include/maskfld.cpp
@@ -432,6 +432,16 @@ word TMask_field::last_key() const
   return (word)u;
 }
 
+
+// Certified 90%
+void TMask_field::reset_key(byte key)
+{
+  CHECK(key>0, "Can't reset key 0");
+  _keys.reset(long(key));
+  if (last_key()==0) _keys.reset(0L);
+}
+
+
 void TMask_field::set_dirty(bool d) 
 {                
   if (_flags.dirty == 3 && d == FALSE)
diff --git a/include/maskfld.h b/include/maskfld.h
index 1109507eb..b1d6503f8 100755
--- a/include/maskfld.h
+++ b/include/maskfld.h
@@ -317,6 +317,8 @@ public:
   // @cmember Setta il campo alla chiave <p key>
   void set_key(byte key) 
   { _keys.set(long(key)); _keys.set(0L);}
+  // @cmember Rimuove il campo dalla chiave <p key>
+  void reset_key(byte key);
   // @cmember Ritorna l'ultima chiave di appartenenza del campo
   word last_key() const;
   
diff --git a/include/relapp.cpp b/include/relapp.cpp
index 3699bef74..95d11ec09 100755
--- a/include/relapp.cpp
+++ b/include/relapp.cpp
@@ -1,4 +1,4 @@
-//      $Id: relapp.cpp,v 1.65 1995-08-29 09:17:39 gianluca Exp $        
+//      $Id: relapp.cpp,v 1.66 1995-09-20 16:56:01 gianluca Exp $        
 #include <mailbox.h>
 #include <sheet.h>
 #include <urldefid.h>
@@ -519,7 +519,13 @@ bool TRelation_application::test_key(byte k, bool err)
 
 // Guy: doesn't change fields
 bool TRelation_application::find(byte k)
-{
+{                         
+  if (changing_keys()) 
+  {
+    delete _maskeys;
+    _maskeys= new TKey_array(_mask);
+  }
+  
   const byte numkeys = _maskeys->items();
 
   if (k == 0)
diff --git a/include/relapp.h b/include/relapp.h
index 3541325ed..f6faa46a9 100755
--- a/include/relapp.h
+++ b/include/relapp.h
@@ -74,6 +74,9 @@ protected:
   // la futura get_mask ritornera' una maschera diversa dalla corrente.
   virtual bool changing_mask(int mode) pure;      
   virtual TMask* get_mask(int mode) pure;           // Richiede la maschera da usare
+
+  // metodo per far forzare la rigenerazione della lista interna di chiavi ad ogni find()
+  virtual bool changing_keys() const { return FALSE; }
   
   virtual TRelation* get_relation() const pure;     // Relazione da modificare
   virtual int read(TMask& m);                       // Legge dalla relazione i valori nella maschera