diff --git a/client/dist/js/LeftAndMain_Subsites.js b/client/dist/js/LeftAndMain_Subsites.js
index 248cc619..1a55e793 100644
--- a/client/dist/js/LeftAndMain_Subsites.js
+++ b/client/dist/js/LeftAndMain_Subsites.js
@@ -1 +1 @@
-!function(){"use strict";var t={311:function(t){t.exports=jQuery}},e={};function i(s){var n=e[s];if(void 0!==n)return n.exports;var r=e[s]={exports:{}};return t[s](r,r.exports,i),r.exports}!function(){var t,e=i(311);(t=e).entwine("ss",(t=>{t("#SubsitesSelect").entwine({onadd(){this.on("change",(function(){window.location.search=t.query.set("SubsiteID",t(this).val())}))}}),t(".cms-container .cms-menu-list li a").entwine({onclick(e){t(".cms-container").loadFragment("admin/subsite_xhr","SubsiteList"),this._super(e)}}),t(".cms-container .SubsiteAdmin .cms-edit-form fieldset.ss-gridfield").entwine({onreload(e){t(".cms-container").loadFragment("admin/subsite_xhr","SubsiteList"),this._super(e)}}),t(".cms-container .tab.subsite-model").entwine({onadd(e){t(".cms-container").loadFragment("admin/subsite_xhr","SubsiteList"),this._super(e)}}),t("#Form_ItemEditForm_AccessAllSubsites").entwine({onmatch(){this.showHideSubsiteList();const e=this;t("#Form_ItemEditForm_AccessAllSubsites input").change((()=>{e.showHideSubsiteList()}))},showHideSubsiteList(){t("#Form_ItemEditForm_Subsites").parent().parent().css("display",t("#Form_ItemEditForm_AccessAllSubsites_1").is(":checked")?"none":"")}}),t(".cms-edit-form").entwine({getChangeTrackerOptions(){const e=void 0===this.entwineData("ChangeTrackerOptions");let i=this._super();return e&&(i=t.extend({},i),i.ignoreFieldSelector+=", input[name=IsSubsite]",this.setChangeTrackerOptions(i)),i}}),t(".cms-edit-form input[name=action_copytosubsite]").entwine({onclick(t){this.closest("form").trigger("submit",[this])}})})),t.entwine("ss.preview",(t=>{t(".cms-preview").entwine({onafterIframeAdjustedForPreview(e,i){const s=t(i).find("meta[name=x-subsite-id]").attr("content");s&&(t(i).find("a").each((function(){const e=t(this).attr("href");void 0===e||e.match(/^http:\/\//)||t(this).attr("href",t.path.addSearchParams(e,{SubsiteID:s}))})),t(i).find("form").each((function(){const e=t(this).attr("action");void 0===e||e.match(/^http:\/\//)||t(this).append(`<input type=hidden name="SubsiteID" value="${s}" >`)})))}})}))}()}();
\ No newline at end of file
+!function(){"use strict";var t={311:function(t){t.exports=jQuery}},e={};function i(s){var n=e[s];if(void 0!==n)return n.exports;var o=e[s]={exports:{}};return t[s](o,o.exports,i),o.exports}!function(){var t,e=i(311);(t=e).entwine("ss",(t=>{t("#SubsitesSelect").entwine({detectSubsiteChange(t){const e="admin_subsite_id";let i=!1;try{localStorage.setItem(e,t),window.addEventListener("storage",(()=>{if(i)return;const s=localStorage.getItem(e);if(s&&t!=s){const t=ss.i18n._t("Admin.SUBSITECHANGED","You've changed subsite in another tab, do you want to reload the page?");i=!0,confirm(t)&&window.location.reload()}}))}catch(t){}},onmatch(){this.detectSubsiteChange(this.find("option[selected]").attr("value"))},onadd(){this.on("change",(function(){window.location.search=t.query.set("SubsiteID",t(this).val())}))}}),t(".cms-container .cms-menu-list li a").entwine({onclick(e){t(".cms-container").loadFragment("admin/subsite_xhr","SubsiteList"),this._super(e)}}),t(".cms-container .SubsiteAdmin .cms-edit-form fieldset.ss-gridfield").entwine({onreload(e){t(".cms-container").loadFragment("admin/subsite_xhr","SubsiteList"),this._super(e)}}),t(".cms-container .tab.subsite-model").entwine({onadd(e){t(".cms-container").loadFragment("admin/subsite_xhr","SubsiteList"),this._super(e)}}),t("#Form_ItemEditForm_AccessAllSubsites").entwine({onmatch(){this.showHideSubsiteList();const e=this;t("#Form_ItemEditForm_AccessAllSubsites input").change((()=>{e.showHideSubsiteList()}))},showHideSubsiteList(){t("#Form_ItemEditForm_Subsites").parent().parent().css("display",t("#Form_ItemEditForm_AccessAllSubsites_1").is(":checked")?"none":"")}}),t(".cms-edit-form").entwine({getChangeTrackerOptions(){const e=void 0===this.entwineData("ChangeTrackerOptions");let i=this._super();return e&&(i=t.extend({},i),i.ignoreFieldSelector+=", input[name=IsSubsite]",this.setChangeTrackerOptions(i)),i}}),t(".cms-edit-form input[name=action_copytosubsite]").entwine({onclick(t){this.closest("form").trigger("submit",[this])}})})),t.entwine("ss.preview",(t=>{t(".cms-preview").entwine({onafterIframeAdjustedForPreview(e,i){const s=t(i).find("meta[name=x-subsite-id]").attr("content");s&&(t(i).find("a").each((function(){const e=t(this).attr("href");void 0===e||e.match(/^http:\/\//)||t(this).attr("href",t.path.addSearchParams(e,{SubsiteID:s}))})),t(i).find("form").each((function(){const e=t(this).attr("action");void 0===e||e.match(/^http:\/\//)||t(this).append(`<input type=hidden name="SubsiteID" value="${s}" >`)})))}})}))}()}();
\ No newline at end of file
diff --git a/client/src/js/LeftAndMain_Subsites.js b/client/src/js/LeftAndMain_Subsites.js
index c0ee6b5f..60f04bcf 100644
--- a/client/src/js/LeftAndMain_Subsites.js
+++ b/client/src/js/LeftAndMain_Subsites.js
@@ -1,9 +1,42 @@
 /* jslint browser: true, nomen: true */
-/* global $, window, jQuery */
+/* global $, ss, window, jQuery */
 (function ($) {
   // eslint-disable-next-line no-shadow
   $.entwine('ss', ($) => {
     $('#SubsitesSelect').entwine({
+      /**
+       * Store current subsite id and ask to reload the page if it detects any change
+       */
+      detectSubsiteChange(selectedId) {
+        const sessionKey = 'admin_subsite_id';
+        let reloadPending = false;
+        try {
+          localStorage.setItem(sessionKey, selectedId);
+
+          window.addEventListener('storage', () => {
+            if (reloadPending) {
+              return;
+            }
+            const tabId = localStorage.getItem(sessionKey);
+            // eslint-disable-next-line eqeqeq
+            if (tabId && selectedId != tabId) {
+              const msg = ss.i18n._t('Admin.SUBSITECHANGED', 'You\'ve changed subsite in another tab, do you want to reload the page?');
+              reloadPending = true; // Don't trigger multiple confirm dialog
+              // eslint-disable-next-line no-alert
+              if (confirm(msg)) {
+                window.location.reload();
+              }
+              // Don't ask again if cancelled
+            }
+          });
+        } catch (e) {
+          // Maybe storage is full or not available, disable this feature and ignore error
+        }
+      },
+
+      onmatch() {
+        this.detectSubsiteChange(this.find('option[selected]').attr('value'));
+      },
       onadd() {
         this.on('change', function () {
           window.location.search = $.query.set('SubsiteID', $(this).val());