diff --git a/datamodels/2.x/itop-config/config.php b/datamodels/2.x/itop-config/config.php
index 5d0ad8370..4ebc1466c 100644
--- a/datamodels/2.x/itop-config/config.php
+++ b/datamodels/2.x/itop-config/config.php
@@ -4,6 +4,7 @@
  * @license     http://opensource.org/licenses/AGPL-3.0
  */
 
+use Combodo\iTop\Application\UI\Base\Component\Alert\Alert;
 use Combodo\iTop\Application\UI\Base\Component\Alert\AlertUIBlockFactory;
 use Combodo\iTop\Application\UI\Base\Component\Button\ButtonUIBlockFactory;
 use Combodo\iTop\Application\UI\Base\Component\Form\Form;
@@ -15,6 +16,10 @@ use Combodo\iTop\Config\Validator\iTopConfigSyntaxValidator;
 
 require_once(APPROOT.'application/startup.inc.php');
 
+const CONFIG_ERROR = 0;
+const CONFIG_WARNING = 1;
+const CONFIG_INFO = 2;
+
 
 /**
  * @param $sContents
@@ -45,31 +50,51 @@ function DBPasswordInNewConfigIsOk($sSafeContent)
 	if ($bIsWindows && (preg_match("@'db_pwd' => '[^%!\"]+',@U", $sSafeContent) === 0)) {
 		return false;
 	}
+
 	return true;
 }
 
 function CheckAsyncTasksRetryConfig(Config $oTempConfig, iTopWebPage $oP)
 {
-    $iWarnings = 0;
-    foreach(get_declared_classes() as $sPHPClass)
-    {
-        $oRefClass = new ReflectionClass($sPHPClass);
-        if ($oRefClass->isSubclassOf('AsyncTask') && !$oRefClass->isAbstract())
-        {
-            $aMessages = AsyncTask::CheckRetryConfig($oTempConfig, $oRefClass->getName());
+	$iWarnings = 0;
+	foreach (get_declared_classes() as $sPHPClass) {
+		$oRefClass = new ReflectionClass($sPHPClass);
+		if ($oRefClass->isSubclassOf('AsyncTask') && !$oRefClass->isAbstract()) {
+			$aMessages = AsyncTask::CheckRetryConfig($oTempConfig, $oRefClass->getName());
 
-            if (count($aMessages) !== 0)
-            {
-                foreach($aMessages as $sMessage)
-                {
-                    $oAlert = AlertUIBlockFactory::MakeForWarning('', $sMessage);
-                    $oP->AddUiBlock($oAlert);
-                    $iWarnings ++;
-                }
-            }
-        }
-    }
-    return $iWarnings;
+			if (count($aMessages) !== 0) {
+				foreach ($aMessages as $sMessage) {
+					$oAlert = AlertUIBlockFactory::MakeForWarning('', $sMessage);
+					$oP->AddUiBlock($oAlert);
+					$iWarnings++;
+				}
+			}
+		}
+	}
+
+	return $iWarnings;
+}
+
+/**
+ * @param \Exception $e
+ *
+ * @return \Combodo\iTop\Application\UI\Base\Component\Alert\Alert
+ */
+function GetAlertFromException(Exception $e): Alert
+{
+	switch ($e->getCode()) {
+		case CONFIG_WARNING:
+			$oAlert = AlertUIBlockFactory::MakeForWarning('', $e->getMessage());
+			break;
+		case CONFIG_INFO:
+			$oAlert = AlertUIBlockFactory::MakeForInformation('', $e->getMessage());
+			break;
+		case CONFIG_ERROR:
+		default:
+			$oAlert = AlertUIBlockFactory::MakeForDanger('', $e->getMessage());
+	}
+
+	return $oAlert;
 }
 
 /////////////////////////////////////////////////////////////////////
@@ -97,111 +122,112 @@ try {
 	$oP->AddUiBlock(TitleUIBlockFactory::MakeForPage(Dict::S('config-edit-title')));
 
 	if (MetaModel::GetConfig()->Get('demo_mode')) {
-		$oAlert = AlertUIBlockFactory::MakeForInformation('', "Sorry, iTop is in <b>demonstration mode</b>: the configuration file cannot be edited.");
-		$oP->AddUiBlock($oAlert);
-	} else {
-		if (MetaModel::GetModuleSetting('itop-config', 'config_editor', '') == 'disabled') {
-			$oAlert = AlertUIBlockFactory::MakeForWarning('', "iTop interactive edition of the configuration as been disabled. See <tt>'config_editor' => 'disabled'</tt> in the configuration file.");
+		throw new Exception(Dict::S('config-not-allowed-in-demo'), CONFIG_INFO);
+	}
+
+	if (MetaModel::GetModuleSetting('itop-config', 'config_editor', '') == 'disabled') {
+		throw new Exception(Dict::S('config-interactive-not-allowed'), CONFIG_WARNING);
+	}
+
+	$sConfigFile = APPROOT.'conf/'.utils::GetCurrentEnvironment().'/config-itop.php';
+
+	$iEditorTopMargin += 9;
+	$sConfigContent = file_get_contents($sConfigFile);
+	$sConfigChecksum = md5($sConfigContent);
+	$sConfig = str_replace("\r\n", "\n", $sConfigContent);
+	$sOriginalConfig = $sConfig;
+
+	if (!empty($sOperation)) {
+		$iEditorTopMargin += 5;
+		$sConfig = utils::ReadParam('new_config', '', false, 'raw_data');
+	}
+
+	try {
+		if ($sOperation == 'revert') {
+			throw new Exception(Dict::S('config-reverted'), CONFIG_WARNING);
+		}
+
+		if ($sOperation == 'save') {
+			$sTransactionId = utils::ReadParam('transaction_id', '', false, 'transaction_id');
+			if (!utils::IsTransactionValid($sTransactionId, true)) {
+				throw new Exception(Dict::S('config-error-transaction'), CONFIG_ERROR);
+			}
+
+			$sChecksum = utils::ReadParam('checksum');
+			if ($sChecksum !== $sConfigChecksum) {
+				throw new Exception(Dict::S('config-error-file-changed'), CONFIG_ERROR);
+			}
+
+			if ($sConfig === $sOriginalConfig) {
+				throw new Exception(Dict::S('config-no-change'), CONFIG_INFO);
+			}
+			TestConfig($sConfig, $oP); // throws exceptions
+
+			@chmod($sConfigFile, 0770); // Allow overwriting the file
+			$sTmpFile = tempnam(SetupUtils::GetTmpDir(), 'itop-cfg-');
+			// Don't write the file as-is since it would allow to inject any kind of PHP code.
+			// Instead, write the interpreted version of the file
+			// Note:
+			// The actual raw PHP code will anyhow be interpreted exactly twice: once in TestConfig() above
+			// and a second time during the load of the Config object below.
+			// If you are really concerned about an iTop administrator crafting some malicious
+			// PHP code inside the config file, then turn off the interactive configuration
+			// editor by adding the configuration parameter:
+			// 'itop-config' => array(
+			//     'config_editor' => 'disabled',
+			// )
+			file_put_contents($sTmpFile, $sConfig);
+			$oTempConfig = new Config($sTmpFile, true);
+			$oTempConfig->WriteToFile($sConfigFile);
+			@unlink($sTmpFile);
+			@chmod($sConfigFile, 0440); // Read-only
+
+			if (DBPasswordInNewConfigIsOk($sConfig)) {
+				$oAlert = AlertUIBlockFactory::MakeForSuccess('', Dict::S('config-saved'));
+			} else {
+				$oAlert = AlertUIBlockFactory::MakeForInformation('', Dict::S('config-saved-warning-db-password'));
+			}
 			$oP->AddUiBlock($oAlert);
-		} else {
-			$sConfigFile = APPROOT.'conf/'.utils::GetCurrentEnvironment().'/config-itop.php';
 
-			$iEditorTopMargin += 9;
-			$sConfig = str_replace("\r\n", "\n", file_get_contents($sConfigFile));
+			$iWarnings = CheckAsyncTasksRetryConfig($oTempConfig, $oP);
+
+			// Read the config from disk after save
+			$sConfigContent = file_get_contents($sConfigFile);
+			$sConfigChecksum = md5($sConfigContent);
+			$sConfig = str_replace("\r\n", "\n", $sConfigContent);
 			$sOriginalConfig = $sConfig;
+		}
+	}
+	catch (Exception $e) {
+		$oAlert = GetAlertFromException($e);
+		$oP->AddUiBlock($oAlert);
+	}
 
-			if (!empty($sOperation)) {
-				$iEditorTopMargin += 5;
-				$sConfig = utils::ReadParam('new_config', '', false, 'raw_data');
-				$sOriginalConfig = utils::ReadParam('prev_config', '', false, 'raw_data');
-			}
+	// (remove EscapeHtml)  N°5914 - Wrong encoding in modules configuration editor
+	$oP->AddUiBlock(new Html('<p>'.Dict::S('config-edit-intro').'</p>'));
 
-			if ($sOperation == 'revert') {
-				$iEditorTopMargin += 5;
-				$oAlert = AlertUIBlockFactory::MakeForWarning('', Dict::S('config-reverted'));
-				$oP->AddUiBlock($oAlert);
-			}
-			if ($sOperation == 'save') {
-				$sTransactionId = utils::ReadParam('transaction_id', '', false, 'transaction_id');
-				if (!utils::IsTransactionValid($sTransactionId, true)) {
-					$iEditorTopMargin += 5;
-					$oAlert = AlertUIBlockFactory::MakeForFailure('', 'Error: invalid Transaction ID. The configuration was <b>NOT</b> modified.');
-					$oP->AddUiBlock($oAlert);
-				} else {
-					if ($sConfig == $sOriginalConfig) {
-						$iEditorTopMargin += 5;
-						$oAlert = AlertUIBlockFactory::MakeForInformation('', Dict::S('config-no-change'));
-						$oP->AddUiBlock($oAlert);
-					} else {
-						try {
-							TestConfig($sConfig, $oP); // throws exceptions
+	$oForm = new Form();
+	$oForm->AddSubBlock(InputUIBlockFactory::MakeForHidden('operation', 'save', 'operation'));
+	$oForm->AddSubBlock(InputUIBlockFactory::MakeForHidden('transaction_id', utils::GetNewTransactionId()));
+	$oForm->AddSubBlock(InputUIBlockFactory::MakeForHidden('checksum', $sConfigChecksum));
 
-							@chmod($sConfigFile, 0770); // Allow overwriting the file
-							$sTmpFile = tempnam(SetupUtils::GetTmpDir(), 'itop-cfg-');
-							// Don't write the file as-is since it would allow to inject any kind of PHP code.
-							// Instead write the interpreted version of the file
-							// Note:
-							// The actual raw PHP code will anyhow be interpreted exactly twice: once in TestConfig() above
-							// and a second time during the load of the Config object below.
-							// If you are really concerned about an iTop administrator crafting some malicious
-							// PHP code inside the config file, then turn off the interactive configuration
-							// editor by adding the configuration parameter:
-							// 'itop-config' => array(
-							//     'config_editor' => 'disabled',
-							// )
-							file_put_contents($sTmpFile, $sConfig);
-							$oTempConfig = new Config($sTmpFile, true);
-							$oTempConfig->WriteToFile($sConfigFile);
-							@unlink($sTmpFile);
-							@chmod($sConfigFile, 0440); // Read-only
+	//--- Cancel button
+	$oCancelButton = ButtonUIBlockFactory::MakeForCancel(Dict::S('config-cancel'), 'cancel_button', null, true, 'cancel_button');
+	$oCancelButton->SetOnClickJsCode("return ResetConfig();");
+	$oForm->AddSubBlock($oCancelButton);
 
-							if (DBPasswordInNewConfigIsOk($sConfig)) {
-								$oAlert = AlertUIBlockFactory::MakeForSuccess('', Dict::S('config-saved'));
-								$iEditorTopMargin += 5;
-							} else {
-								$oAlert = AlertUIBlockFactory::MakeForInformation('', Dict::S('config-saved-warning-db-password'));
-								$iEditorTopMargin += 5;
-							}
-							$oP->AddUiBlock($oAlert);
+	//--- Submit button
+	$oSubmitButton = ButtonUIBlockFactory::MakeForPrimaryAction(Dict::S('config-apply'), null, Dict::S('config-apply'), true, 'submit_button');
+	$oForm->AddSubBlock($oSubmitButton);
 
-							$iWarnings = CheckAsyncTasksRetryConfig($oTempConfig, $oP);
-							$iEditorTopMargin += 5*$iWarnings;
+	//--- Config editor
+	$oForm->AddSubBlock(InputUIBlockFactory::MakeForHidden('prev_config', $sOriginalConfig, 'prev_config'));
+	$oForm->AddSubBlock(InputUIBlockFactory::MakeForHidden('new_config', $sOriginalConfig));
+	$oForm->AddHtml("<div id =\"new_config\" style=\"position: absolute; top: ".$iEditorTopMargin."em; bottom: 0; left: 5px; right: 5px;\"></div>");
+	$oP->AddUiBlock($oForm);
 
-							$sOriginalConfig = str_replace("\r\n", "\n", file_get_contents($sConfigFile));
-						}
-						catch (Exception $e) {
-							$oAlert = AlertUIBlockFactory::MakeForDanger('', $e->getMessage());
-							$iEditorTopMargin += 5;
-							$oP->AddUiBlock($oAlert);
-						}
-					}
-				}
-			}
-
-			// (remove EscapeHtml)  N°5914 - Wrong encoding in modules configuration editor
-			$oP->AddUiBlock(new Html('<p>'.Dict::S('config-edit-intro').'</p>'));
-
-			$oForm = new Form();
-			$oForm->AddSubBlock(InputUIBlockFactory::MakeForHidden('operation', 'save'));
-			$oForm->AddSubBlock(InputUIBlockFactory::MakeForHidden('transaction_id', utils::GetNewTransactionId()));
-
-			//--- Cancel button
-			$oCancelButton = ButtonUIBlockFactory::MakeForCancel(Dict::S('config-cancel'), 'cancel_button', null, true, 'cancel_button');
-			$oCancelButton->SetOnClickJsCode("return ResetConfig();");
-			$oForm->AddSubBlock($oCancelButton);
-
-			//--- Submit button
-			$oSubmitButton = ButtonUIBlockFactory::MakeForPrimaryAction(Dict::S('config-apply'), null, Dict::S('config-apply'), true, 'submit_button');
-			$oForm->AddSubBlock($oSubmitButton);
-
-			//--- Config editor
-			$oForm->AddSubBlock(InputUIBlockFactory::MakeForHidden('prev_config', $sOriginalConfig, 'prev_config'));
-			$oForm->AddSubBlock(InputUIBlockFactory::MakeForHidden('new_config', $sConfig));
-			$oForm->AddHtml("<div id =\"new_config\" style=\"position: absolute; top: ".$iEditorTopMargin."em; bottom: 0; left: 5px; right: 5px;\"></div>");
-			$oP->AddUiBlock($oForm);
-
-			$oP->add_script(
-				<<<'JS'
+	$oP->add_script(
+		<<<'JS'
 var EditorUtils = (function() {
 	var STORAGE_RANGE_KEY = 'cfgEditorRange';
 	var STORAGE_LINE_KEY = 'cfgEditorFirstline';
@@ -271,9 +297,8 @@ var EditorUtils = (function() {
 	};
 })();
 JS
-		);
-		$oP->add_ready_script(
-			<<<'JS'
+	);
+	$oP->add_ready_script(<<<'JS'
 var editor = ace.edit("new_config");
 
 var configurationSource = $('input[name="new_config"]');
@@ -314,31 +339,25 @@ editorForm.on('submit', function() {
 EditorUtils.restoreEditorDisplay(editor);
 editor.focus();
 JS
-		);
+	);
 
-			$sConfirmCancel = addslashes(Dict::S('config-confirm-cancel'));
-			$oP->add_script(<<<JS
+	$sConfirmCancel = addslashes(Dict::S('config-confirm-cancel'));
+	$oP->add_script(<<<JS
 function ResetConfig()
 {
-    var editor = ace.edit("new_config");
 	$("#operation").attr('value', 'revert');
-	var prevConfig = $('#prev_config');
-	if (editor.getValue() != prevConfig.val())
+	if (confirm('$sConfirmCancel'))
 	{
-		if (confirm('$sConfirmCancel'))
-		{
-			$('input[name="new_config"]').val(prevConfig.val());
-			return true;
-		}
+		$('input[name="new_config"]').val(prevConfig.val());
+		return true;
 	}
 	return false;
 }
 JS
-			);
-		}
-	}
+	);
 } catch (Exception $e) {
-	$oP->p('<b>'.$e->getMessage().'</b>');
+	$oAlert = GetAlertFromException($e);
+	$oP->AddUiBlock($oAlert);
 }
 
 $oP->output();
diff --git a/datamodels/2.x/itop-config/dictionaries/en.dict.itop-config.php b/datamodels/2.x/itop-config/dictionaries/en.dict.itop-config.php
index 249bf6652..c3e38d3d1 100644
--- a/datamodels/2.x/itop-config/dictionaries/en.dict.itop-config.php
+++ b/datamodels/2.x/itop-config/dictionaries/en.dict.itop-config.php
@@ -36,4 +36,8 @@ Dict::Add('EN US', 'English', 'English', array(
 	'config-parse-error' => 'Line %2$d: %1$s.<br/>The file has NOT been updated.',
 	'config-current-line' => 'Editing line: %1$s',
 	'config-saved-warning-db-password' => 'Successfully recorded, but the backup won\'t work due to unsupported characters in the database password.',
+	'config-error-transaction' => 'Error: invalid Transaction ID. The configuration was <b>NOT</b> modified.',
+	'config-error-file-changed' => 'Error: The configuration was changed on the server, the configuration has not been saved',
+	'config-not-allowed-in-demo' => 'Sorry, '.ITOP_APPLICATION_SHORT.' is in <b>demonstration mode</b>: the configuration file cannot be edited.',
+	'config-interactive-not-allowed' => ITOP_APPLICATION_SHORT." interactive edition of the configuration as been disabled. See <code>'config_editor' => 'disabled'</code> in the configuration file.",
 ));
diff --git a/datamodels/2.x/itop-config/dictionaries/fr.dict.itop-config.php b/datamodels/2.x/itop-config/dictionaries/fr.dict.itop-config.php
index 2d1ba746a..5a3347a5b 100644
--- a/datamodels/2.x/itop-config/dictionaries/fr.dict.itop-config.php
+++ b/datamodels/2.x/itop-config/dictionaries/fr.dict.itop-config.php
@@ -8,7 +8,7 @@
 Dict::Add('FR FR', 'French', 'Français', array(
 
 	'Menu:ConfigEditor' => 'Configuration Générale',
-	'config-edit-title' => 'Editeur du Fichier de Configuration',
+	'config-edit-title' => 'Éditeur du Fichier de Configuration',
 	'config-edit-intro' => 'Attention: une configuration incorrecte peut rendre '.ITOP_APPLICATION_SHORT.' inopérant pour tous les utilisateurs!',
 	'config-apply' => 'Enregistrer',
 	'config-apply-title' => 'Enregistrer (Ctrl+S)',
@@ -20,4 +20,8 @@ Dict::Add('FR FR', 'French', 'Français', array(
 	'config-parse-error' => 'Ligne %2$d: %1$s.<br/>Le fichier n\'a PAS été modifié.',
 	'config-current-line' => 'Ligne en édition : %1$s',
 	'config-saved-warning-db-password' => 'Configuration enregistrée. Les sauvegardes ne fonctionneront pas à cause du format du pot de passe de la base.',
+	'config-error-transaction' => "Erreur : La transaction n'est plus valide. Les modifications n'ont <b>PAS</b> été enregistrées.",
+	'config-error-file-changed' => "Erreur : La configuration a été modifiée sur le serveur par une autre action. Les modifications n'ont <b>PAS</b> été enregistrées.",
+	'config-not-allowed-in-demo' => 'Désolé, '.ITOP_APPLICATION_SHORT.' est en <b>mode démonstration</b> : la configuration ne peut pas être modifiée.',
+	'config-interactive-not-allowed' => "La modification interactive de la configuration n'est pas autorisée. Voir le paramètre <code>'config_editor' => 'disabled'</code> dans le fichier de configuration.",
 ));