diff --git a/include/isam.cpp b/include/isam.cpp
index 4478e7334..0250a8130 100755
--- a/include/isam.cpp
+++ b/include/isam.cpp
@@ -670,7 +670,7 @@ HIDDEN int cisread(int fhnd, int knum, TRectype& record, int mode, TRecnotype& c
   TString256 keystr;
   char* key = keystr.get_buffer();
   
-  int err = NOERR ;
+  int err = NOERR;
   do
   {
     if (rmode>=_isequal && rmode<=_isgteq)
@@ -2967,6 +2967,7 @@ int TRectype::compare_key(
 
 // @xref <mf TRectype::build_key>
 {
+/* Vecchio modo con molte operazioni su stringhe e molte chiamate a rec_des()!
   TString256 key1 = build_key(key);
   TString256 key2 = rec.build_key(key);
   if (skip_last > 0)
@@ -2984,6 +2985,27 @@ int TRectype::compare_key(
     }  
   }
   const int res = strcmp(key1, key2);
+*/
+  const char* key1 = build_key(key);
+  const char* key2 = rec.build_key(key);
+  int res = 0;
+  if (skip_last > 0)
+  {                
+    int maxlen = 0;
+    const RecDes& rd = *rec_des();
+    const KeyDes& kd = rd.Ky[key-1];
+    const int last = kd.NkFields-skip_last;
+    for (int l = 0; l < last; l++)
+    {
+      const int nf = kd.FieldSeq[l] % MaxFields; 
+      const RecFieldDes& rf = rd.Fd[nf];  
+      maxlen += rf.Len;
+    }  
+    res = strncmp(key1, key2, maxlen);
+  }
+  else
+    res = strcmp(key1, key2);
+
   return res;
 }
 
diff --git a/include/mask.h b/include/mask.h
index c2608e9e0..3321f9d2d 100755
--- a/include/mask.h
+++ b/include/mask.h
@@ -137,6 +137,8 @@ protected:
   bool check_current_field() const;
   // @cmember Mostra la prossima/precedente pagina
   virtual void next_page(int p);
+  // @cmember Cambia arbitrariamente il nome del file (uso molto raro)
+  void set_source_file(const char* name) { _source_file = name; }
 
   // @access Public Member
 public:
diff --git a/include/maskfld.cpp b/include/maskfld.cpp
index 5dc800c35..3a99a4d56 100755
--- a/include/maskfld.cpp
+++ b/include/maskfld.cpp
@@ -2503,7 +2503,7 @@ KEY TBrowse::run()
   
     for (const char* i = _inp_id.get(0); i; i = _inp_id.get())
     {            
-      if (*i != '"' && strchr(i, '@') == NULL)
+      if (*i != '\0' && *i != '"' && strchr(i, '@') == NULL)
       {
         const short id = field().atodlg(i);
         const TEditable_field& f = field(id);
diff --git a/include/relapp.h b/include/relapp.h
index 9a420d725..8592daab9 100755
--- a/include/relapp.h
+++ b/include/relapp.h
@@ -165,7 +165,7 @@ protected:
   //        (ricerca, inserimento, modifica) avviene sempre in due tempi: <mf TRelation_application::changing_mask> e 
   //        <mf TRelation_application::get_mask>.  Cio' serve per gestire correttamente le applicazioni
   //          con maschere multiple.
-  virtual bool changing_mask(int mode) pure;
+  virtual bool changing_mask(int mode) { return false; }
   // @cmember Richiede la maschera da usare
   virtual TMask* get_mask(int mode) pure;