diff --git a/src/public/app/widgets/ribbon_widgets/classic_editor_toolbar.js b/src/public/app/widgets/ribbon_widgets/classic_editor_toolbar.ts
similarity index 88%
rename from src/public/app/widgets/ribbon_widgets/classic_editor_toolbar.js
rename to src/public/app/widgets/ribbon_widgets/classic_editor_toolbar.ts
index 3f9152c1b..c22036fc4 100644
--- a/src/public/app/widgets/ribbon_widgets/classic_editor_toolbar.js
+++ b/src/public/app/widgets/ribbon_widgets/classic_editor_toolbar.ts
@@ -64,6 +64,9 @@ const TPL = `\
  * The ribbon item is active by default for text notes, as long as they are not in read-only mode.
  */
 export default class ClassicEditorToolbar extends NoteContextAwareWidget {
+
+    private observer: MutationObserver;
+
     constructor() {
         super();
         this.observer = new MutationObserver((e) => this.#onDropdownStateChanged(e));
@@ -83,7 +86,7 @@ export default class ClassicEditorToolbar extends NoteContextAwareWidget {
 
         if (utils.isMobile()) {
             // The virtual keyboard obscures the editing toolbar so we have to reposition by calculating the height of the keyboard.
-            window.visualViewport.addEventListener("resize", () => this.#adjustPosition());
+            window.visualViewport?.addEventListener("resize", () => this.#adjustPosition());
             window.addEventListener("scroll", () => this.#adjustPosition());
 
             // Observe when a dropdown is expanded to apply a style that allows the dropdown to be visible, since we can't have the element both visible and the toolbar scrollable.
@@ -95,13 +98,13 @@ export default class ClassicEditorToolbar extends NoteContextAwareWidget {
         }
     }
 
-    #onDropdownStateChanged(e) {
-        const dropdownActive = e.map((e) => e.target.ariaExpanded === "true").reduce((acc, e) => acc && e);
+    #onDropdownStateChanged(e: MutationRecord[]) {
+        const dropdownActive = e.map((e) => (e.target as any).ariaExpanded === "true").reduce((acc, e) => acc && e);
         this.$widget[0].classList.toggle("dropdown-active", dropdownActive);
     }
 
     #adjustPosition() {
-        let bottom = window.innerHeight - window.visualViewport.height;
+        let bottom = window.innerHeight - (window.visualViewport?.height || 0);
 
         if (bottom === 0) {
             // The keyboard is not visible, align it to the launcher bar instead.
@@ -125,11 +128,11 @@ export default class ClassicEditorToolbar extends NoteContextAwareWidget {
             return false;
         }
 
-        if (this.note.type !== "text") {
+        if (!this.note || this.note.type !== "text") {
             return false;
         }
 
-        if (await this.noteContext.isReadOnly()) {
+        if (await this.noteContext?.isReadOnly()) {
             return false;
         }