diff --git a/js/pages/backoffice/on-ready.js b/js/pages/backoffice/on-ready.js
new file mode 100644
index 000000000..93949c2f6
--- /dev/null
+++ b/js/pages/backoffice/on-ready.js
@@ -0,0 +1,63 @@
+/*
+ * @copyright   Copyright (C) 2010-2021 Combodo SARL
+ * @license     http://opensource.org/licenses/AGPL-3.0
+ */
+
+/*
+ * Here we should put all the "static" (no variable) JS code that needs to be evaluated on DOM ready
+ */
+
+$(document).ready(function () {
+	// AJAX calls handling
+	// - Custom headers
+	$(document).ajaxSend(function (event, jqxhr, options) {
+		jqxhr.setRequestHeader('X-Combodo-Ajax', 'true');
+	});
+	// - Error messages regarding the error code
+	$(document).ajaxError(function (event, jqxhr, options) {
+		// User is not logged ing
+		if (jqxhr.status == 401) {
+			const oUserDisconnectedDialog = $('#ibo-user-disconnected-dialog');
+			// Create dialog widget if not already instantiated
+			if (oUserDisconnectedDialog.data('uiDialog') === undefined) {
+				oUserDisconnectedDialog.removeClass('ibo-is-hidden');
+				oUserDisconnectedDialog.dialog({
+					modal: true,
+					title: Dict.S('UI:DisconnectedDlgTitle'),
+					close: function () {
+						$(this).dialog('close');
+					},
+					minWidth: 400,
+					buttons: [
+						{
+							text: Dict.S('UI:LoginAgain'),
+							click: function () {
+								window.location.href = GetAbsoluteUrlAppRoot()+'pages/UI.php'
+							}
+						},
+						{
+							text: Dict.S('UI:StayOnThePage'),
+							click: function () {
+								$(this).dialog('close');
+							}
+						}
+					]
+				});
+			}
+			// Just open it otherwise
+			else {
+				oUserDisconnectedDialog.dialog('open');
+			}
+		}
+	});
+	// - Successful
+	$(document).ajaxSuccess(function () {
+		// Async. markup, small timeout to allow markup to be built if necessary
+		setTimeout(function () {
+			CombodoTooltip.InitAllNonInstantiatedTooltips();
+			CombodoBackofficeToolbox.InitCodeHighlighting();
+			// Initialize date / datetime pickers if needed
+			PrepareWidgets();
+		}, 500);
+	});
+});
diff --git a/sources/application/WebPage/iTopWebPage.php b/sources/application/WebPage/iTopWebPage.php
index 1994e1c8d..0e6046063 100644
--- a/sources/application/WebPage/iTopWebPage.php
+++ b/sources/application/WebPage/iTopWebPage.php
@@ -153,6 +153,7 @@ class iTopWebPage extends NiceWebPage implements iTabbedPage
 		$this->add_linked_script(utils::GetAbsoluteUrlAppRoot().'js/mousetrap/mousetrap-record.min.js');
 		$this->add_linked_script(utils::GetAbsoluteUrlAppRoot().'js/pages/backoffice/keyboard-shortcuts.js');
 		$this->add_linked_script(utils::GetAbsoluteUrlAppRoot().'js/pages/backoffice/toolbox.js');
+		$this->add_linked_script(utils::GetAbsoluteUrlAppRoot().'js/pages/backoffice/on-ready.js');
 	}
 
 	/**
@@ -173,6 +174,10 @@ class iTopWebPage extends NiceWebPage implements iTabbedPage
 		$this->add_dict_entry('UI:Datatables:Language:Processing');
 		$this->add_dict_entries('UI:Newsroom');
 
+		// User not logged in dialog
+		$this->add_dict_entry('UI:DisconnectedDlgTitle');
+		$this->add_dict_entry('UI:LoginAgain');
+		$this->add_dict_entry('UI:StayOnThePage');
 	}
 
 	/**
@@ -210,10 +215,6 @@ class iTopWebPage extends NiceWebPage implements iTabbedPage
 	 */
 	protected function PrepareLayout()
 	{
-		$sJSDisconnectedMessage = json_encode(Dict::S('UI:DisconnectedDlgMessage'));
-		$sJSTitle = json_encode(Dict::S('UI:DisconnectedDlgTitle'));
-		$sJSLoginAgain = json_encode(Dict::S('UI:LoginAgain'));
-		$sJSStayOnThePage = json_encode(Dict::S('UI:StayOnThePage'));
 		$aDaysMin = array(
 			Dict::S('DayOfWeek-Sunday-Min'),
 			Dict::S('DayOfWeek-Monday-Min'),
@@ -353,34 +354,6 @@ JS
 	// $('#ModalDlg').dialog({ autoOpen: false, modal: true, width: 0.8*docWidth, height: 'auto', maxHeight: $(window).height() - 50 }); // JQuery UI dialogs
 	ShowDebug();
 	
-	$(document).ajaxSend(function(event, jqxhr, options) {
-		jqxhr.setRequestHeader('X-Combodo-Ajax', 'true');
-	});
-	$(document).ajaxError(function(event, jqxhr, options) {
-		if (jqxhr.status == 401)
-		{
-			$('<div>'+$sJSDisconnectedMessage+'</div>').dialog({
-				modal:true,
-				title: $sJSTitle,
-				close: function() { $(this).remove(); },
-				minWidth: 400,
-				buttons: [
-					{ text: $sJSLoginAgain, click: function() { window.location.href= GetAbsoluteUrlAppRoot()+'pages/UI.php' } },
-					{ text: $sJSStayOnThePage, click: function() { $(this).dialog('close'); } }
-				]
-			});
-		}
-	});
-	$(document).ajaxSuccess(function(){
-		// Async. markup, small timeout to allow markup to be built if necessary
-		setTimeout(function(){
-			CombodoTooltip.InitAllNonInstantiatedTooltips();
-			CombodoBackofficeToolbox.InitCodeHighlighting();
-			// Initialize date / datetime pickers if needed 
-			PrepareWidgets();
-		}, 500);
-	});
-	
 	// Default values for blockui
 	$.blockUI.defaults.css = {}; 
 	$.blockUI.defaults.message= '<i class="fas fa-fw fa-spin fa-sync"></i>'; 
diff --git a/templates/pages/backoffice/itopwebpage/layout.html.twig b/templates/pages/backoffice/itopwebpage/layout.html.twig
index 32c233c33..8924d5735 100644
--- a/templates/pages/backoffice/itopwebpage/layout.html.twig
+++ b/templates/pages/backoffice/itopwebpage/layout.html.twig
@@ -28,6 +28,7 @@
 			<div style="display:none" title="ex2" id="ex2">Please wait...</div>
 			<div style="display:none" title="dialog" id="ModalDlg"></div>
 			<div style="display:none" id="ajax_content"></div>
+			<div class="ibo-is-hidden" id="ibo-user-disconnected-dialog">{{ 'UI:DisconnectedDlgMessage'|dict_s }}</div>
 		</div>
 	{% endif %}
 {% endblock %}