diff --git a/src/edt/edt/edtPlugin.cc b/src/edt/edt/edtPlugin.cc
index 5493273b5..ec50d70c6 100644
--- a/src/edt/edt/edtPlugin.cc
+++ b/src/edt/edt/edtPlugin.cc
@@ -88,7 +88,10 @@ void get_inst_options (std::vector < std::pair<std::string, std::string> > &opti
 
 edt::RecentConfigurationPage::ConfigurationDescriptor inst_cfg_descriptors[] =
 {
-  edt::RecentConfigurationPage::ConfigurationDescriptor (cfg_edit_inst_cell_name, tl::to_string (tr ("Cell name")), edt::RecentConfigurationPage::Text),
+  edt::RecentConfigurationPage::ConfigurationDescriptor (cfg_edit_inst_lib_name, tl::to_string (tr ("Library")), edt::RecentConfigurationPage::Text),
+  edt::RecentConfigurationPage::ConfigurationDescriptor (cfg_edit_inst_cell_name, tl::to_string (tr ("Cell")), edt::RecentConfigurationPage::Text),
+  //  encode this into the cell?
+  edt::RecentConfigurationPage::ConfigurationDescriptor (cfg_edit_inst_pcell_parameters, tl::to_string (tr ("PCell parameters")), edt::RecentConfigurationPage::PCellParamters),
   edt::RecentConfigurationPage::ConfigurationDescriptor (cfg_edit_inst_angle, tl::to_string (tr ("Angle")), edt::RecentConfigurationPage::Double),
   edt::RecentConfigurationPage::ConfigurationDescriptor (cfg_edit_inst_mirror, tl::to_string (tr ("Mirror")), edt::RecentConfigurationPage::Bool),
   edt::RecentConfigurationPage::ConfigurationDescriptor (cfg_edit_inst_scale, tl::to_string (tr ("Scale")), edt::RecentConfigurationPage::Double),
@@ -104,7 +107,7 @@ edt::RecentConfigurationPage::ConfigurationDescriptor inst_cfg_descriptors[] =
 static 
 void get_inst_editor_options_pages (std::vector<edt::EditorOptionsPage *> &ret, lay::Dispatcher *dispatcher)
 {
-  ret.push_back (new RecentConfigurationPage (dispatcher, 22, tl::to_string (tr ("Recent")),
+  ret.push_back (new RecentConfigurationPage (dispatcher, "edit-recent-inst-param",
                         &inst_cfg_descriptors[0], &inst_cfg_descriptors[sizeof (inst_cfg_descriptors) / sizeof (inst_cfg_descriptors[0])]));
   ret.push_back (new EditorOptionsInstPCellParam (dispatcher));
   ret.push_back (new EditorOptionsInst (dispatcher));
diff --git a/src/edt/edt/edtRecentConfigurationPage.cc b/src/edt/edt/edtRecentConfigurationPage.cc
index 52d06d484..0d86a5ce5 100644
--- a/src/edt/edt/edtRecentConfigurationPage.cc
+++ b/src/edt/edt/edtRecentConfigurationPage.cc
@@ -29,6 +29,8 @@
 namespace edt
 {
 
+static const size_t max_entries = 100;
+
 void
 RecentConfigurationPage::init ()
 {
@@ -36,6 +38,8 @@ RecentConfigurationPage::init ()
   ly->setMargin (0);
 
   mp_tree_widget = new QTreeWidget (this);
+  mp_tree_widget->setRootIsDecorated (false);
+  mp_tree_widget->setUniformRowHeights (true);
   ly->addWidget (mp_tree_widget);
 
   mp_tree_widget->setColumnCount (int (m_cfg.size ()));
@@ -46,7 +50,7 @@ RecentConfigurationPage::init ()
   }
   mp_tree_widget->setHeaderLabels (column_labels);
 
-  update_list ();
+  update_list (get_stored_values ());
 }
 
 RecentConfigurationPage::~RecentConfigurationPage ()
@@ -54,9 +58,59 @@ RecentConfigurationPage::~RecentConfigurationPage ()
   //  .. nothing yet ..
 }
 
+std::string RecentConfigurationPage::title () const
+{
+  return tl::to_string (tr ("Recent"));
+}
+
+int RecentConfigurationPage::order () const
+{
+  return 100;
+}
+
+std::list<std::vector<std::string> >
+RecentConfigurationPage::get_stored_values () const
+{
+  std::string serialized_list = dispatcher ()->config_get (m_recent_cfg_name);
+
+  std::list<std::vector<std::string> > values;
+  tl::Extractor ex (serialized_list.c_str ());
+  while (! ex.at_end ()) {
+
+    values.push_back (std::vector<std::string> ());
+    while (! ex.at_end () && ! ex.test (";")) {
+      values.back ().push_back (std::string ());
+      ex.read_word_or_quoted (values.back ().back ());
+      ex.test (",");
+    }
+
+  }
+
+  return values;
+}
+
+void
+RecentConfigurationPage::set_stored_values (const std::list<std::vector<std::string> > &values) const
+{
+  std::string serialized_list;
+  for (std::list<std::vector<std::string> >::const_iterator v = values.begin (); v != values.end (); ++v) {
+    if (v != values.begin ()) {
+      serialized_list += ";";
+    }
+    for (std::vector<std::string>::const_iterator s = v->begin (); s != v->end (); ++s) {
+      serialized_list += tl::to_word_or_quoted_string (*s);
+      serialized_list += ",";
+    }
+  }
+
+  dispatcher ()->config_set (m_recent_cfg_name, serialized_list);
+}
+
 void
 render_to (QTreeWidgetItem *item, int column, const std::string &v, RecentConfigurationPage::ConfigurationRendering rendering)
 {
+  //  store original value
+  item->setData (column, Qt::UserRole, tl::to_qstring (v));
 
   // @@@ rendering
   item->setText (column, tl::to_qstring (v));
@@ -64,10 +118,10 @@ render_to (QTreeWidgetItem *item, int column, const std::string &v, RecentConfig
 }
 
 void
-RecentConfigurationPage::update_list ()
+RecentConfigurationPage::update_list (const std::list<std::vector<std::string> > &stored_values)
 {
   int row = 0;
-  for (std::list<std::vector<std::string> >::const_iterator v = m_stored_values.begin (); v != m_stored_values.end (); ++v, ++row) {
+  for (std::list<std::vector<std::string> >::const_iterator v = stored_values.begin (); v != stored_values.end (); ++v, ++row) {
 
     QTreeWidgetItem *item = 0;
     if (row < mp_tree_widget->topLevelItemCount ()) {
@@ -102,16 +156,24 @@ RecentConfigurationPage::commit_recent (lay::Dispatcher *root)
     values.push_back (root->config_get (c->cfg_name));
   }
 
-  for (std::list<std::vector<std::string> >::iterator v = m_stored_values.begin (); v != m_stored_values.end (); ++v) {
+  std::list<std::vector<std::string> > stored_values = get_stored_values ();
+
+  for (std::list<std::vector<std::string> >::iterator v = stored_values.begin (); v != stored_values.end (); ++v) {
     if (*v == values) {
-      m_stored_values.erase (v);
+      stored_values.erase (v);
       break;
     }
   }
 
-  m_stored_values.push_front (values);
+  stored_values.push_front (values);
 
-  update_list ();
+  while (stored_values.size () > max_entries) {
+    stored_values.erase (--stored_values.end ());
+  }
+
+  set_stored_values (stored_values);
+
+  update_list (stored_values);
 }
 
 }
diff --git a/src/edt/edt/edtRecentConfigurationPage.h b/src/edt/edt/edtRecentConfigurationPage.h
index 3cb290401..37bd35fcb 100644
--- a/src/edt/edt/edtRecentConfigurationPage.h
+++ b/src/edt/edt/edtRecentConfigurationPage.h
@@ -66,29 +66,29 @@ public:
   };
 
   template <class Iter>
-  RecentConfigurationPage (lay::Dispatcher *dispatcher, int order, const std::string &title, Iter begin_cfg, Iter end_cfg)
-    : EditorOptionsPage (dispatcher), m_title (title), m_order (order), m_cfg (begin_cfg, end_cfg)
+  RecentConfigurationPage (lay::Dispatcher *dispatcher, const std::string &recent_cfg_name, Iter begin_cfg, Iter end_cfg)
+    : EditorOptionsPage (dispatcher), m_recent_cfg_name (recent_cfg_name), m_cfg (begin_cfg, end_cfg)
   {
     init ();
   }
 
   virtual ~RecentConfigurationPage ();
 
-  virtual std::string title () const { return m_title; }
-  virtual int order () const { return m_order; }
+  virtual std::string title () const;
+  virtual int order () const;
   virtual void apply (lay::Dispatcher * /*root*/) { }
   virtual void setup (lay::Dispatcher * /*root*/) { }
   virtual void commit_recent (lay::Dispatcher *root);
 
 private:
-  std::string m_title;
-  int m_order;
+  std::string m_recent_cfg_name;
   std::list<ConfigurationDescriptor> m_cfg;
   QTreeWidget *mp_tree_widget;
-  std::list<std::vector<std::string> > m_stored_values;
 
   void init ();
-  void update_list ();
+  void update_list (const std::list<std::vector<std::string> > &stored_values);
+  std::list<std::vector<std::string> > get_stored_values () const;
+  void set_stored_values (const std::list<std::vector<std::string> > &values) const;
 };
 
 }
diff --git a/src/edt/edt/edtService.cc b/src/edt/edt/edtService.cc
index f479b1c56..c035d6698 100644
--- a/src/edt/edt/edtService.cc
+++ b/src/edt/edt/edtService.cc
@@ -60,45 +60,6 @@ ac_from_buttons (unsigned int buttons)
 
 // -------------------------------------------------------------
 
-std::string pcell_parameters_to_string (const std::map<std::string, tl::Variant> &parameters)
-{
-  std::string param;
-
-  param = "!";  //  flags PCells
-  for (std::map<std::string, tl::Variant>::const_iterator p = parameters.begin (); p != parameters.end (); ++p) {
-    param += tl::to_word_or_quoted_string (p->first);
-    param += ":";
-    param += p->second.to_parsable_string ();
-    param += ";";
-  }
-
-  return param;
-}
-
-std::map<std::string, tl::Variant> pcell_parameters_from_string (const std::string &s)
-{
-  tl::Extractor ex (s.c_str ());
-  std::map<std::string, tl::Variant> pm;
-
-  ex.test ("!");
-
-  try {
-    while (! ex.at_end ()) {
-      std::string n;
-      ex.read_word_or_quoted (n);
-      ex.test (":");
-      ex.read (pm.insert (std::make_pair (n, tl::Variant ())).first->second);
-      ex.test (";");
-    }
-  } catch (...) {
-    //  ignore errors
-  }
-
-  return pm;
-}
-
-// -------------------------------------------------------------
-
 Service::Service (db::Manager *manager, lay::LayoutView *view, db::ShapeIterator::flags_type flags)
   : lay::ViewService (view->view_object_widget ()), 
     lay::Editable (view),
diff --git a/src/edt/edt/edtServiceImpl.cc b/src/edt/edt/edtServiceImpl.cc
index 8f65a7e7a..637617ef4 100644
--- a/src/edt/edt/edtServiceImpl.cc
+++ b/src/edt/edt/edtServiceImpl.cc
@@ -1417,6 +1417,14 @@ InstService::do_mouse_transform (const db::DPoint &p, db::DFTrans trans)
   m_column_x = c.x ();
   m_column_y = c.y ();
 
+  dispatcher ()->config_set (cfg_edit_inst_angle, m_angle);
+  dispatcher ()->config_set (cfg_edit_inst_mirror, m_mirror);
+  dispatcher ()->config_set (cfg_edit_inst_row_x, m_row_x);
+  dispatcher ()->config_set (cfg_edit_inst_row_y, m_row_y);
+  dispatcher ()->config_set (cfg_edit_inst_column_x, m_column_x);
+  dispatcher ()->config_set (cfg_edit_inst_column_y, m_column_y);
+  dispatcher ()->config_end ();
+
   //  honour the new transformation
   do_mouse_move (p);
 }
@@ -1535,78 +1543,171 @@ InstService::configure (const std::string &name, const std::string &value)
 
   if (name == cfg_edit_inst_pcell_parameters) {
 
-    m_pcell_parameters = pcell_parameters_from_string (value);
-    m_is_pcell = ! value.empty ();
+    std::map<std::string, tl::Variant> pcp = pcell_parameters_from_string (value);
+    if (pcp != m_pcell_parameters) {
+
+      m_pcell_parameters = pcp;
+      m_is_pcell = ! value.empty ();
+
+      m_needs_update = true;
+
+    }
 
-    m_needs_update = true;
     return true; // taken
 
   }
 
   if (name == cfg_edit_inst_place_origin) {
-    tl::from_string (value, m_place_origin);
-    m_needs_update = true;
+
+    bool f;
+    tl::from_string (value, f);
+
+    if (f != m_place_origin) {
+      m_place_origin = f;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   if (name == cfg_edit_inst_scale) {
-    tl::from_string (value, m_scale);
-    m_needs_update = true;
+
+    double s;
+    tl::from_string (value, s);
+
+    if (fabs (s - m_scale) > 1e-10) {
+      m_scale = s;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   if (name == cfg_edit_inst_angle) {
-    tl::from_string (value, m_angle);
-    m_needs_update = true;
+
+    double a;
+    tl::from_string (value, a);
+
+    if (fabs (a - m_angle) > 1e-10) {
+      m_angle = a;
+      m_needs_update = true;
+    }
+
     return true; // taken
   }
 
   if (name == cfg_edit_inst_mirror) {
-    tl::from_string (value, m_mirror);
-    m_needs_update = true;
+
+    bool f;
+    tl::from_string (value, f);
+
+    if (f != m_mirror) {
+      m_mirror = f;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   if (name == cfg_edit_inst_array) {
-    tl::from_string (value, m_array);
-    m_needs_update = true;
+
+    bool f;
+    tl::from_string (value, f);
+
+    if (f != m_array) {
+      m_array = f;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   if (name == cfg_edit_inst_rows) {
-    tl::from_string (value, m_rows);
-    m_needs_update = true;
+
+    unsigned int v;
+    tl::from_string (value, v);
+
+    if (v != m_rows) {
+      m_rows = v;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   if (name == cfg_edit_inst_row_x) {
-    tl::from_string (value, m_row_x);
-    m_needs_update = true;
+
+    double v;
+    tl::from_string (value, v);
+
+    if (! db::coord_traits<double>::equal (m_row_x, v)) {
+      m_row_x = v;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   if (name == cfg_edit_inst_row_y) {
-    tl::from_string (value, m_row_y);
-    m_needs_update = true;
+
+    double v;
+    tl::from_string (value, v);
+
+    if (! db::coord_traits<double>::equal (m_row_y, v)) {
+      m_row_y = v;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   if (name == cfg_edit_inst_columns) {
-    tl::from_string (value, m_columns);
-    m_needs_update = true;
+
+    unsigned int v;
+    tl::from_string (value, v);
+
+    if (v != m_columns) {
+      m_columns = v;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   if (name == cfg_edit_inst_column_x) {
-    tl::from_string (value, m_column_x);
-    m_needs_update = true;
+
+    double v;
+    tl::from_string (value, v);
+
+    if (! db::coord_traits<double>::equal (m_column_x, v)) {
+      m_column_x = v;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   if (name == cfg_edit_inst_column_y) {
-    tl::from_string (value, m_column_y);
-    m_needs_update = true;
+
+    double v;
+    tl::from_string (value, v);
+
+    if (! db::coord_traits<double>::equal (m_column_y, v)) {
+      m_column_y = v;
+      m_needs_update = true;
+    }
+
     return true; // taken
+
   }
 
   return edt::Service::configure (name, value);
diff --git a/src/edt/edt/edtUtils.cc b/src/edt/edt/edtUtils.cc
index 7cc997bf7..a4833a0a1 100644
--- a/src/edt/edt/edtUtils.cc
+++ b/src/edt/edt/edtUtils.cc
@@ -35,6 +35,45 @@
 
 namespace edt {
 
+// -------------------------------------------------------------
+
+std::string pcell_parameters_to_string (const std::map<std::string, tl::Variant> &parameters)
+{
+  std::string param;
+
+  param = "!";  //  flags PCells
+  for (std::map<std::string, tl::Variant>::const_iterator p = parameters.begin (); p != parameters.end (); ++p) {
+    param += tl::to_word_or_quoted_string (p->first);
+    param += ":";
+    param += p->second.to_parsable_string ();
+    param += ";";
+  }
+
+  return param;
+}
+
+std::map<std::string, tl::Variant> pcell_parameters_from_string (const std::string &s)
+{
+  tl::Extractor ex (s.c_str ());
+  std::map<std::string, tl::Variant> pm;
+
+  ex.test ("!");
+
+  try {
+    while (! ex.at_end ()) {
+      std::string n;
+      ex.read_word_or_quoted (n);
+      ex.test (":");
+      ex.read (pm.insert (std::make_pair (n, tl::Variant ())).first->second);
+      ex.test (";");
+    }
+  } catch (...) {
+    //  ignore errors
+  }
+
+  return pm;
+}
+
 // -------------------------------------------------------------
 //  SelectionIterator implementation
 
diff --git a/src/edt/edt/edtUtils.h b/src/edt/edt/edtUtils.h
index a4a512e7a..460f9a12e 100644
--- a/src/edt/edt/edtUtils.h
+++ b/src/edt/edt/edtUtils.h
@@ -47,6 +47,16 @@ namespace edt {
 
 class Service;
 
+/**
+ *  @brief Serializes PCell parameters to a string
+ */
+std::string pcell_parameters_to_string (const std::map<std::string, tl::Variant> &parameters);
+
+/**
+ *  @brief Deerializes PCell parameters from a string
+ */
+std::map<std::string, tl::Variant> pcell_parameters_from_string (const std::string &s);
+
 /**
  *  @brief Fetch PCell parameters from a cell and merge the guiding shapes into them
  *