diff --git a/web_src/js/components/DiffFileTree.vue b/web_src/js/components/DiffFileTree.vue
index e2934b967eb0e..010f05100b190 100644
--- a/web_src/js/components/DiffFileTree.vue
+++ b/web_src/js/components/DiffFileTree.vue
@@ -4,6 +4,7 @@ import {toggleElem} from '../utils/dom.ts';
 import {diffTreeStore} from '../modules/diff-file.ts';
 import {setFileFolding} from '../features/file-fold.ts';
 import {onMounted, onUnmounted} from 'vue';
+import {getLocalStorageSetting, setLocalStorageSetting} from '../modules/storage.ts';
 
 const LOCAL_STORAGE_KEY = 'diff_file_tree_visible';
 
@@ -11,7 +12,7 @@ const store = diffTreeStore();
 
 onMounted(() => {
   // Default to true if unset
-  store.fileTreeIsVisible = localStorage.getItem(LOCAL_STORAGE_KEY) !== 'false';
+  store.fileTreeIsVisible = getLocalStorageSetting(LOCAL_STORAGE_KEY) !== 'false';
   document.querySelector('.diff-toggle-file-tree-button')!.addEventListener('click', toggleVisibility);
 
   hashChangeListener();
@@ -43,7 +44,7 @@ function toggleVisibility() {
 
 function updateVisibility(visible: boolean) {
   store.fileTreeIsVisible = visible;
-  localStorage.setItem(LOCAL_STORAGE_KEY, store.fileTreeIsVisible.toString());
+  setLocalStorageSetting(LOCAL_STORAGE_KEY, store.fileTreeIsVisible.toString());
   updateState(store.fileTreeIsVisible);
 }
 
diff --git a/web_src/js/components/RepoActionView.vue b/web_src/js/components/RepoActionView.vue
index 357a2ba10eefa..1cf4ae968917f 100644
--- a/web_src/js/components/RepoActionView.vue
+++ b/web_src/js/components/RepoActionView.vue
@@ -8,6 +8,7 @@ import {renderAnsi} from '../render/ansi.ts';
 import {POST, DELETE} from '../modules/fetch.ts';
 import type {IntervalId} from '../types.ts';
 import {toggleFullScreen} from '../utils.ts';
+import {getLocalStorageSetting, setLocalStorageSetting} from '../modules/storage.ts';
 
 // see "models/actions/status.go", if it needs to be used somewhere else, move it to a shared file like "types/actions.ts"
 type RunStatus = 'unknown' | 'waiting' | 'running' | 'success' | 'failure' | 'cancelled' | 'skipped' | 'blocked';
@@ -73,7 +74,7 @@ type LocaleStorageOptions = {
 
 function getLocaleStorageOptions(): LocaleStorageOptions {
   try {
-    const optsJson = localStorage.getItem('actions-view-options');
+    const optsJson = getLocalStorageSetting('actions-view-options');
     if (optsJson) return JSON.parse(optsJson);
   } catch {}
   // if no options in localStorage, or failed to parse, return default options
@@ -224,7 +225,7 @@ export default defineComponent({
   methods: {
     saveLocaleStorageOptions() {
       const opts: LocaleStorageOptions = {autoScroll: this.optionAlwaysAutoScroll, expandRunning: this.optionAlwaysExpandRunning};
-      localStorage.setItem('actions-view-options', JSON.stringify(opts));
+      setLocalStorageSetting('actions-view-options', JSON.stringify(opts));
     },
 
     // get the job step logs container ('.job-step-logs')
diff --git a/web_src/js/features/citation.ts b/web_src/js/features/citation.ts
index d5ecb52e72a7f..509bb75505ea6 100644
--- a/web_src/js/features/citation.ts
+++ b/web_src/js/features/citation.ts
@@ -1,5 +1,6 @@
 import {getCurrentLocale} from '../utils.ts';
 import {fomanticQuery} from '../modules/fomantic/base.ts';
+import {getLocalStorageSetting, setLocalStorageSetting} from '../modules/storage.ts';
 
 const {pageData} = window.config;
 
@@ -38,7 +39,7 @@ export async function initCitationFileCopyContent() {
   if ((!citationCopyApa && !citationCopyBibtex) || !inputContent) return;
 
   const updateUi = () => {
-    const isBibtex = (localStorage.getItem('citation-copy-format') || defaultCitationFormat) === 'bibtex';
+    const isBibtex = (getLocalStorageSetting('citation-copy-format') || defaultCitationFormat) === 'bibtex';
     const copyContent = (isBibtex ? citationCopyBibtex : citationCopyApa).getAttribute('data-text')!;
     inputContent.value = copyContent;
     citationCopyBibtex.classList.toggle('primary', isBibtex);
@@ -55,12 +56,12 @@ export async function initCitationFileCopyContent() {
     updateUi();
 
     citationCopyApa.addEventListener('click', () => {
-      localStorage.setItem('citation-copy-format', 'apa');
+      setLocalStorageSetting('citation-copy-format', 'apa');
       updateUi();
     });
 
     citationCopyBibtex.addEventListener('click', () => {
-      localStorage.setItem('citation-copy-format', 'bibtex');
+      setLocalStorageSetting('citation-copy-format', 'bibtex');
       updateUi();
     });
 
diff --git a/web_src/js/features/comp/ComboMarkdownEditor.ts b/web_src/js/features/comp/ComboMarkdownEditor.ts
index 234a96b2af17c..4791450e8d697 100644
--- a/web_src/js/features/comp/ComboMarkdownEditor.ts
+++ b/web_src/js/features/comp/ComboMarkdownEditor.ts
@@ -24,6 +24,7 @@ import {DropzoneCustomEventReloadFiles, initDropzone} from '../dropzone.ts';
 import {createTippy} from '../../modules/tippy.ts';
 import {fomanticQuery} from '../../modules/fomantic/base.ts';
 import type EasyMDE from 'easymde';
+import {addLocalStorageChangeListener, getLocalStorageSetting, setLocalStorageSetting} from '../../modules/storage.ts';
 
 /**
  * validate if the given textarea is non-empty.
@@ -47,6 +48,21 @@ export function validateTextareaNonEmpty(textarea: HTMLTextAreaElement) {
   return true;
 }
 
+/** Returns whether the user currently has the monospace font setting enabled */
+function isMonospaceEnabled() {
+  return getLocalStorageSetting('markdown-editor-monospace') === 'true';
+}
+
+/** Apply font to the provided or all textareas on the page and optionally save on localStorage */
+function applyMonospace(enabled: boolean, {textarea, save}: {textarea?: HTMLTextAreaElement, save?: boolean}) {
+  for (const el of textarea ? [textarea] : document.querySelectorAll('.markdown-text-editor')) {
+    el.classList.toggle('tw-font-mono', enabled);
+  }
+  if (save) {
+    setLocalStorageSetting('markdown-editor-monospace', String(enabled));
+  }
+}
+
 type Heights = {
   minHeight?: string,
   height?: string,
@@ -141,20 +157,25 @@ export class ComboMarkdownEditor {
     }
 
     const monospaceButton = this.container.querySelector('.markdown-switch-monospace')!;
-    const monospaceEnabled = localStorage?.getItem('markdown-editor-monospace') === 'true';
+    const monospaceEnabled = isMonospaceEnabled();
+    applyMonospace(monospaceEnabled, {textarea: this.textarea, save: false});
     const monospaceText = monospaceButton.getAttribute(monospaceEnabled ? 'data-disable-text' : 'data-enable-text')!;
     monospaceButton.setAttribute('data-tooltip-content', monospaceText);
     monospaceButton.setAttribute('aria-checked', String(monospaceEnabled));
     monospaceButton.addEventListener('click', (e) => {
       e.preventDefault();
-      const enabled = localStorage?.getItem('markdown-editor-monospace') !== 'true';
-      localStorage.setItem('markdown-editor-monospace', String(enabled));
-      this.textarea.classList.toggle('tw-font-mono', enabled);
+      const enabled = !isMonospaceEnabled();
+      applyMonospace(enabled, {save: true});
       const text = monospaceButton.getAttribute(enabled ? 'data-disable-text' : 'data-enable-text')!;
       monospaceButton.setAttribute('data-tooltip-content', text);
       monospaceButton.setAttribute('aria-checked', String(enabled));
     });
 
+    // apply setting when it was changed in another tab
+    addLocalStorageChangeListener('markdown-editor-monospace', () => {
+      applyMonospace(isMonospaceEnabled(), {save: false});
+    });
+
     if (this.supportEasyMDE) {
       const easymdeButton = this.container.querySelector('.markdown-switch-easymde')!;
       easymdeButton.addEventListener('click', async (e) => {
@@ -403,10 +424,10 @@ export class ComboMarkdownEditor {
   }
 
   get userPreferredEditor(): string {
-    return window.localStorage.getItem(`markdown-editor-${this.previewMode ?? 'default'}`) || '';
+    return getLocalStorageSetting(`markdown-editor-${this.previewMode ?? 'default'}`) || '';
   }
   set userPreferredEditor(s: string) {
-    window.localStorage.setItem(`markdown-editor-${this.previewMode ?? 'default'}`, s);
+    setLocalStorageSetting(`markdown-editor-${this.previewMode ?? 'default'}`, s);
   }
 }
 
diff --git a/web_src/js/features/repo-common.ts b/web_src/js/features/repo-common.ts
index ac753805d326c..98f76588cddfd 100644
--- a/web_src/js/features/repo-common.ts
+++ b/web_src/js/features/repo-common.ts
@@ -6,6 +6,7 @@ import RepoActivityTopAuthors from '../components/RepoActivityTopAuthors.vue';
 import {createApp} from 'vue';
 import {toOriginUrl} from '../utils/url.ts';
 import {createTippy} from '../modules/tippy.ts';
+import {getLocalStorageSetting, setLocalStorageSetting} from '../modules/storage.ts';
 
 async function onDownloadArchive(e: Event) {
   e.preventDefault();
@@ -57,7 +58,7 @@ function initCloneSchemeUrlSelection(parent: Element) {
   const tabSsh = parent.querySelector('.repo-clone-ssh');
   const tabTea = parent.querySelector('.repo-clone-tea');
   const updateClonePanelUi = function() {
-    let scheme = localStorage.getItem('repo-clone-protocol')!;
+    let scheme = getLocalStorageSetting('repo-clone-protocol')!;
     if (!['https', 'ssh', 'tea'].includes(scheme)) {
       scheme = 'https';
     }
@@ -114,15 +115,15 @@ function initCloneSchemeUrlSelection(parent: Element) {
   updateClonePanelUi();
   // tabSsh or tabHttps might not both exist, eg: guest view, or one is disabled by the server
   tabHttps?.addEventListener('click', () => {
-    localStorage.setItem('repo-clone-protocol', 'https');
+    setLocalStorageSetting('repo-clone-protocol', 'https');
     updateClonePanelUi();
   });
   tabSsh?.addEventListener('click', () => {
-    localStorage.setItem('repo-clone-protocol', 'ssh');
+    setLocalStorageSetting('repo-clone-protocol', 'ssh');
     updateClonePanelUi();
   });
   tabTea?.addEventListener('click', () => {
-    localStorage.setItem('repo-clone-protocol', 'tea');
+    setLocalStorageSetting('repo-clone-protocol', 'tea');
     updateClonePanelUi();
   });
   elCloneUrlInput.addEventListener('focus', () => {
diff --git a/web_src/js/modules/storage.ts b/web_src/js/modules/storage.ts
new file mode 100644
index 0000000000000..a5f2dc0e4b2bb
--- /dev/null
+++ b/web_src/js/modules/storage.ts
@@ -0,0 +1,18 @@
+/** Get a setting from localStorage */
+export function getLocalStorageSetting(key: string) {
+  return localStorage?.getItem(key);
+}
+
+/** Set a setting in localStorage */
+export function setLocalStorageSetting(key: string, value: string) {
+  return localStorage?.setItem(key, value);
+}
+
+/** Add a listener to the 'storage' event for given setting key. This event only fires in non-current tabs. */
+export function addLocalStorageChangeListener(key: string, listener: (e: StorageEvent) => void) {
+  window.addEventListener('storage', (e: StorageEvent) => {
+    if (e.storageArea === localStorage && e.key === key) {
+      listener(e);
+    }
+  });
+}