fix: Settings dialog blocking return to Automatic

fixes:# 9501

src/lib/gui/dialogs/SettingsDialog.cpp

@@ -264,10 +264,15 @@ void SettingsDialog::loadFromConfig()
   ui->lblDebugWarning->setVisible(Settings::value(Settings::Log::Level).toInt() > 4);
 
   ui->comboInterface->setCurrentText(Settings::value(Settings::Core::Interface).toString());
-  if (ui->comboInterface->currentIndex() < 0)
+  if (ui->comboInterface->currentIndex() <= 0) {
     ui->comboInterface->setCurrentIndex(0);
+    m_interfaceSetOnLoad = false;
+  } else {
+    m_interfaceSetOnLoad = true;
+  }
 
   qDebug() << "load from config done";
+
   updateControls();
 }
 
@@ -381,9 +386,9 @@ void SettingsDialog::logLevelChanged()
 bool SettingsDialog::isModified() const
 {
   const auto processMode = Settings::value(Settings::Core::ProcessMode).value<Settings::ProcessMode>();
-  const auto interfaceSet = ui->comboInterface->currentIndex();
+  const bool ignoreInterface = !m_interfaceSetOnLoad && (ui->comboInterface->currentIndex() == 0);
 
-  return (
+  bool modified =
       (ui->sbPort->value() != Settings::value(Settings::Core::Port).toInt()) ||
       (ui->comboLogLevel->currentIndex() != Settings::value(Settings::Log::Level).toInt()) ||
       (ui->groupLogToFile->isChecked() != Settings::value(Settings::Log::ToFile).toBool()) ||
@@ -398,13 +403,15 @@ bool SettingsDialog::isModified() const
       (ui->cbShowVersion->isChecked() != Settings::value(Settings::Gui::ShowVersionInTitle).toBool()) ||
       (ui->rbIconMono->isChecked() != Settings::value(Settings::Gui::SymbolicTrayIcon).toBool()) ||
       (ui->groupService->isChecked() != (processMode == Settings::ProcessMode::Service)) ||
-      ((ui->comboInterface->currentText() != Settings::value(Settings::Core::Interface).toString()) && interfaceSet) ||
       (ui->lineTlsCertPath->text() != Settings::value(Settings::Security::Certificate).toString()) ||
       (ui->comboTlsKeyLength->currentText() != Settings::value(Settings::Security::KeySize).toString()) ||
       (ui->groupSecurity->isChecked() != Settings::value(Settings::Security::TlsEnabled).toBool()) ||
       (ui->cbRequireClientCert->isChecked() != Settings::value(Settings::Security::CheckPeers).toBool()) ||
-      (I18N::nativeTo639Name(ui->comboLanguage->currentText()) != Settings::value(Settings::Core::Language).toString())
+      (I18N::nativeTo639Name(ui->comboLanguage->currentText()) != Settings::value(Settings::Core::Language).toString());
-  );
+
+  if (!ignoreInterface)
+    modified = modified || ui->comboInterface->currentText() != Settings::value(Settings::Core::Interface).toString();
+  return modified;
 }
 
 bool SettingsDialog::isDefault() const

src/lib/gui/dialogs/SettingsDialog.h

@@ -84,6 +84,7 @@ private:
    */
   void setButtonBoxEnabledButtons() const;
 
+  bool m_interfaceSetOnLoad = false;
   std::unique_ptr<Ui::SettingsDialog> ui;
   const IServerConfig &m_serverConfig;
 };