// wxComboBox
 //-----------------------------------------------------------------------------
 
-IMPLEMENT_DYNAMIC_CLASS(wxComboBox,wxControl)
-
 BEGIN_EVENT_TABLE(wxComboBox, wxControl)
     EVT_SIZE(wxComboBox::OnSize)
     EVT_CHAR(wxComboBox::OnChar)
     EnableEvents();
 }
 
-wxString wxComboBox::GetValue() const
+wxString wxComboBox::DoGetValue() const
 {
     GtkEntry *entry = GTK_ENTRY( GTK_COMBO(m_widget)->entry );
     wxString tmp( wxGTK_CONV_BACK( gtk_entry_get_text( entry ) ) );
 
     GtkWidget *entry = GTK_COMBO(m_widget)->entry;
     gtk_editable_delete_text( GTK_EDITABLE(entry), (gint)from, (gint)to );
-    if (value.IsNull()) return;
+    if ( value.empty() ) return;
     gint pos = (gint)to;
 
 #if wxUSE_UNICODE