diff --git a/src/speechclient.hh b/src/speechclient.hh
index 1e3e8262..b72224fc 100644
--- a/src/speechclient.hh
+++ b/src/speechclient.hh
@@ -5,6 +5,7 @@
 #include "config.hh"
 #include <QTextToSpeech>
 #include <memory>
+#include <QDebug>
 
 class SpeechClient: public QObject
 {
@@ -40,7 +41,7 @@ public:
       sp( std::make_unique< QTextToSpeech >( e.engine_name ) ),
       engine( e )
     {
-      qDebug() << "initialize tts" << e.engine_name;
+      qDebug() << QStringLiteral( "initialize tts" ) << e.engine_name;
 #if ( QT_VERSION >= QT_VERSION_CHECK( 6, 0, 0 ) )
       if ( !sp || sp->state() == QTextToSpeech::Error )
         return;
@@ -75,10 +76,6 @@ public:
   bool tell( QString const & text, int volume, int rate ) const;
   bool tell( QString const & text ) const;
 
- signals:
-  void started( bool ok );
-  void finished();
-
  private:
   std::unique_ptr< InternalData > internalData;
 };
diff --git a/src/ui/editdictionaries.cc b/src/ui/editdictionaries.cc
index b38738c8..3761c202 100644
--- a/src/ui/editdictionaries.cc
+++ b/src/ui/editdictionaries.cc
@@ -32,18 +32,18 @@ EditDictionaries::EditDictionaries( QWidget * parent,
   // the initial group readings so that if no edits were really done, we won't
   // be changing groups.
   origCfg.groups = groups->getGroups();
-  origCfg.dictionaryOrder = orderAndProps->getCurrentDictionaryOrder();
+  origCfg.dictionaryOrder      = orderAndProps->getCurrentDictionaryOrder();
   origCfg.inactiveDictionaries = orderAndProps->getCurrentInactiveDictionaries();
 
   ui.setupUi( this );
 
-  setWindowIcon( QIcon(":/icons/dictionary.svg") );
+  setWindowIcon( QIcon( ":/icons/dictionary.svg" ) );
 
   ui.tabs->clear();
 
-  ui.tabs->addTab( &sources, QIcon(":/icons/sources.png"), tr( "&Sources" ) );
-  ui.tabs->addTab( orderAndProps.get(), QIcon( ":/icons/book.svg" ), tr( "&Dictionaries" ) );
-  ui.tabs->addTab( groups.get(), QIcon(":/icons/bookcase.svg"), tr( "&Groups" ) );
+  ui.tabs->addTab( &sources, QIcon( ":/icons/sources.png" ), tr( "&Sources" ) );
+  ui.tabs->addTab( orderAndProps, QIcon( ":/icons/book.svg" ), tr( "&Dictionaries" ) );
+  ui.tabs->addTab( groups, QIcon( ":/icons/bookcase.svg" ), tr( "&Groups" ) );
 
   connect( ui.buttons, &QDialogButtonBox::clicked, this, &EditDictionaries::buttonBoxClicked );
 
@@ -57,7 +57,7 @@ EditDictionaries::EditDictionaries( QWidget * parent,
   helpAction.setShortcutContext( Qt::WidgetWithChildrenShortcut );
 
   connect( &helpAction, &QAction::triggered, [ this ]() {
-    if ( ui.tabs->currentWidget() == this->groups.get() ) {
+    if ( ui.tabs->currentWidget() == this->groups ) {
       Help::openHelpWebpage( Help::section::manage_groups );
     }
     else {
@@ -240,8 +240,8 @@ void EditDictionaries::acceptChangedSources( bool rebuildGroups )
     orderAndProps = new OrderAndProps( this, savedOrder, savedInactive, dictionaries );
     groups        = new Groups( this, dictionaries, savedGroups, orderAndProps->getCurrentDictionaryOrder() );
 
-    ui.tabs->insertTab( 1, orderAndProps.get(), QIcon( ":/icons/book.svg" ), tr( "&Dictionaries" ) );
-    ui.tabs->insertTab( 2, groups.get(), QIcon( ":/icons/bookcase.svg" ), tr( "&Groups" ) );
+    ui.tabs->insertTab( 1, orderAndProps, QIcon( ":/icons/book.svg" ), tr( "&Dictionaries" ) );
+    ui.tabs->insertTab( 2, groups, QIcon( ":/icons/bookcase.svg" ), tr( "&Groups" ) );
     connect( groups, &Groups::showDictionaryInfo, this, &EditDictionaries::showDictionaryInfo );
     connect( orderAndProps, &OrderAndProps::showDictionaryHeadwords, this, &EditDictionaries::showDictionaryHeadwords );
 
diff --git a/src/ui/groups_widgets.cc b/src/ui/groups_widgets.cc
index d2c16f44..ae97d6b7 100644
--- a/src/ui/groups_widgets.cc
+++ b/src/ui/groups_widgets.cc
@@ -575,8 +575,8 @@ void DictGroupsWidget::populate( Config::Groups const & groups,
     connect( gr, &DictGroupWidget::showDictionaryInfo,this, &DictGroupsWidget::showDictionaryInfo );
     connect( gr->getModel(), &DictListModel::contentChanged, this, &DictGroupsWidget::tabDataChanged );
 
-    QString toolTipStr = "\"" + tabText( x ) + "\"\n" + tr( "Dictionaries: " )
-      + QString::number( getModelAt( x )->getCurrentDictionaries().size() );
+    QString toolTipStr =
+      "\"" + tabText( x ) + "\"\n" + tr( "Dictionaries: " ) + QString::number( getDictionaryCountAt( x ) );
     setTabToolTip( x, toolTipStr );
   }
 
@@ -617,13 +617,31 @@ DictListModel * DictGroupsWidget::getCurrentModel() const
 DictListModel * DictGroupsWidget::getModelAt( int current ) const
 {
   if ( current >= 0 && current < count() ) {
-    const auto w = (DictGroupWidget *)widget( current );
+    const auto w = static_cast< DictGroupWidget * >( widget( current ) );
+    if ( !w )
+      return nullptr;
     return w->getModel();
   }
 
   return nullptr;
 }
 
+int DictGroupsWidget::getDictionaryCountAt( int current ) const
+{
+  const auto model = getModelAt( current );
+  if ( !model )
+    return 0;
+  return model->getCurrentDictionaries().size();
+}
+
+std::vector< sptr< Dictionary::Class > > DictGroupsWidget::getDictionaryAt( int current ) const
+{
+  const auto model = getModelAt( current );
+  if ( !model )
+    return {};
+  return model->getCurrentDictionaries();
+}
+
 QItemSelectionModel * DictGroupsWidget::getCurrentSelectionModel() const
 {
   const int current = currentIndex();
@@ -653,8 +671,8 @@ int DictGroupsWidget::addNewGroup( QString const & name )
 
   connect( gr->getModel(), &DictListModel::contentChanged, this, &DictGroupsWidget::tabDataChanged );
 
-  const QString toolTipStr = "\"" + tabText( idx ) + "\"\n" + tr( "Dictionaries: " )
-    + QString::number( getModelAt( idx )->getCurrentDictionaries().size() );
+  const QString toolTipStr =
+    "\"" + tabText( idx ) + "\"\n" + tr( "Dictionaries: " ) + QString::number( getDictionaryCountAt( idx ) );
   setTabToolTip( idx, toolTipStr );
   return idx;
 }
@@ -746,6 +764,8 @@ void DictGroupsWidget::addAutoGroups()
     // add dictionaries into the current group
     QVector< sptr< Dictionary::Class > > vd = dictMap[ gr ];
     DictListModel * model                 = getModelAt( idx );
+    if ( !model )
+      continue;
     for( int i = 0; i < vd.count(); i++ )
       model->addRow(QModelIndex(), vd.at( i ) );
   }
@@ -850,6 +870,9 @@ void DictGroupsWidget::addGroupBasedOnMap( const QMultiMap<QString, sptr<Diction
     const auto idx        = addUniqueGroup( group );
     DictListModel * model = getModelAt( idx );
 
+    if ( !model ) {
+      continue;
+    }
     for ( const auto & dict : groupToDicts.values( group ) ) {
       model->addRow( QModelIndex(), dict );
     }
@@ -939,10 +962,13 @@ void DictGroupsWidget::combineGroups( int source, int target )
   if( source < 0 || source >= count() || target < 0 || target >= count() )
     return;
 
-  vector< sptr< Dictionary::Class > > const & dicts = getModelAt( source )->getCurrentDictionaries();
+  vector< sptr< Dictionary::Class > > const & dicts = getDictionaryAt( source );
 
   const auto model = getModelAt( target );
 
+  if ( !model )
+    return;
+
   disconnect( model, &DictListModel::contentChanged, this, &DictGroupsWidget::tabDataChanged );
 
   for ( const auto & dict : dicts ) {
diff --git a/src/ui/groups_widgets.hh b/src/ui/groups_widgets.hh
index f3729ed0..176f4e2e 100644
--- a/src/ui/groups_widgets.hh
+++ b/src/ui/groups_widgets.hh
@@ -193,6 +193,8 @@ public:
   DictListModel * getCurrentModel() const;
 
   DictListModel * getModelAt( int current ) const;
+  int getDictionaryCountAt( int current ) const;
+  std::vector< sptr< Dictionary::Class > > getDictionaryAt( int current ) const;
 
   QItemSelectionModel * getCurrentSelectionModel() const;