diff --git a/web/app.js b/web/app.js
index be1bcd67a..5a990175f 100644
--- a/web/app.js
+++ b/web/app.js
@@ -1770,7 +1770,7 @@ const PDFViewerApplication = {
   forceRendering() {
     this.pdfRenderingQueue.printing = !!this.printService;
     this.pdfRenderingQueue.isThumbnailViewEnabled =
-      this.pdfSidebar.isThumbnailViewVisible;
+      this.pdfSidebar.visibleView === SidebarView.THUMBS;
     this.pdfRenderingQueue.renderHighestPriority();
   },
 
@@ -2266,7 +2266,7 @@ function webViewerPageRendered({ pageNumber, error }) {
   }
 
   // Use the rendered page to set the corresponding thumbnail image.
-  if (PDFViewerApplication.pdfSidebar.isThumbnailViewVisible) {
+  if (PDFViewerApplication.pdfSidebar.visibleView === SidebarView.THUMBS) {
     const pageView = PDFViewerApplication.pdfViewer.getPageView(
       /* index = */ pageNumber - 1
     );
@@ -2343,21 +2343,19 @@ function webViewerPresentationModeChanged(evt) {
   PDFViewerApplication.pdfViewer.presentationModeState = evt.state;
 }
 
-function webViewerSidebarViewChanged(evt) {
+function webViewerSidebarViewChanged({ view }) {
   PDFViewerApplication.pdfRenderingQueue.isThumbnailViewEnabled =
-    PDFViewerApplication.pdfSidebar.isThumbnailViewVisible;
+    view === SidebarView.THUMBS;
 
   if (PDFViewerApplication.isInitialViewSet) {
     // Only update the storage when the document has been loaded *and* rendered.
-    PDFViewerApplication.store?.set("sidebarView", evt.view).catch(() => {
+    PDFViewerApplication.store?.set("sidebarView", view).catch(() => {
       // Unable to write to storage.
     });
   }
 }
 
-function webViewerUpdateViewarea(evt) {
-  const location = evt.location;
-
+function webViewerUpdateViewarea({ location }) {
   if (PDFViewerApplication.isInitialViewSet) {
     // Only update the storage when the document has been loaded *and* rendered.
     PDFViewerApplication.store
@@ -2592,7 +2590,7 @@ function webViewerPageChanging({ pageNumber, pageLabel }) {
   PDFViewerApplication.toolbar.setPageNumber(pageNumber, pageLabel);
   PDFViewerApplication.secondaryToolbar.setPageNumber(pageNumber);
 
-  if (PDFViewerApplication.pdfSidebar.isThumbnailViewVisible) {
+  if (PDFViewerApplication.pdfSidebar.visibleView === SidebarView.THUMBS) {
     PDFViewerApplication.pdfThumbnailViewer.scrollThumbnailIntoView(pageNumber);
   }
 }
diff --git a/web/pdf_sidebar.js b/web/pdf_sidebar.js
index e2c0b201f..9e69a7327 100644
--- a/web/pdf_sidebar.js
+++ b/web/pdf_sidebar.js
@@ -68,6 +68,7 @@ class PDFSidebar {
     this.isOpen = false;
     this.active = SidebarView.THUMBS;
     this.isInitialViewSet = false;
+    this.isInitialEventDispatched = false;
 
     /**
      * Callback used when the sidebar has been opened/closed, to ensure that
@@ -98,13 +99,14 @@ class PDFSidebar {
     this.eventBus = eventBus;
     this.l10n = l10n;
 
-    this._addEventListeners();
+    this.#addEventListeners();
   }
 
   reset() {
     this.isInitialViewSet = false;
+    this.isInitialEventDispatched = false;
 
-    this._hideUINotification(/* reset = */ true);
+    this.#hideUINotification(/* reset = */ true);
     this.switchView(SidebarView.THUMBS);
 
     this.outlineButton.disabled = false;
@@ -120,22 +122,6 @@ class PDFSidebar {
     return this.isOpen ? this.active : SidebarView.NONE;
   }
 
-  get isThumbnailViewVisible() {
-    return this.isOpen && this.active === SidebarView.THUMBS;
-  }
-
-  get isOutlineViewVisible() {
-    return this.isOpen && this.active === SidebarView.OUTLINE;
-  }
-
-  get isAttachmentsViewVisible() {
-    return this.isOpen && this.active === SidebarView.ATTACHMENTS;
-  }
-
-  get isLayersViewVisible() {
-    return this.isOpen && this.active === SidebarView.LAYERS;
-  }
-
   /**
    * @param {number} view - The sidebar view that should become visible,
    *                        must be one of the values in {SidebarView}.
@@ -149,13 +135,15 @@ class PDFSidebar {
     // If the user has already manually opened the sidebar, immediately closing
     // it would be bad UX; also ignore the "unknown" sidebar view value.
     if (view === SidebarView.NONE || view === SidebarView.UNKNOWN) {
-      this._dispatchEvent();
+      this.#dispatchEvent();
       return;
     }
-    // Prevent dispatching two back-to-back `sidebarviewchanged` events,
-    // since `this._switchView` dispatched the event if the view changed.
-    if (!this._switchView(view, /* forceOpen */ true)) {
-      this._dispatchEvent();
+    this.switchView(view, /* forceOpen = */ true);
+
+    // Prevent dispatching two back-to-back "sidebarviewchanged" events,
+    // since `this.switchView` dispatched the event if the view changed.
+    if (!this.isInitialEventDispatched) {
+      this.#dispatchEvent();
     }
   }
 
@@ -166,14 +154,6 @@ class PDFSidebar {
    *                                The default value is `false`.
    */
   switchView(view, forceOpen = false) {
-    this._switchView(view, forceOpen);
-  }
-
-  /**
-   * @returns {boolean} Indicating if `this._dispatchEvent` was called.
-   * @private
-   */
-  _switchView(view, forceOpen = false) {
     const isViewChanged = view !== this.active;
     let shouldForceRendering = false;
 
@@ -181,9 +161,8 @@ class PDFSidebar {
       case SidebarView.NONE:
         if (this.isOpen) {
           this.close();
-          return true; // Closing will trigger rendering and dispatch the event.
         }
-        return false;
+        return; // Closing will trigger rendering and dispatch the event.
       case SidebarView.THUMBS:
         if (this.isOpen && isViewChanged) {
           shouldForceRendering = true;
@@ -191,22 +170,22 @@ class PDFSidebar {
         break;
       case SidebarView.OUTLINE:
         if (this.outlineButton.disabled) {
-          return false;
+          return;
         }
         break;
       case SidebarView.ATTACHMENTS:
         if (this.attachmentsButton.disabled) {
-          return false;
+          return;
         }
         break;
       case SidebarView.LAYERS:
         if (this.layersButton.disabled) {
-          return false;
+          return;
         }
         break;
       default:
-        console.error(`PDFSidebar._switchView: "${view}" is not a valid view.`);
-        return false;
+        console.error(`PDFSidebar.switchView: "${view}" is not a valid view.`);
+        return;
     }
     // Update the active view *after* it has been validated above,
     // in order to prevent setting it to an invalid state.
@@ -238,16 +217,15 @@ class PDFSidebar {
 
     if (forceOpen && !this.isOpen) {
       this.open();
-      return true; // Opening will trigger rendering and dispatch the event.
+      return; // Opening will trigger rendering and dispatch the event.
     }
     if (shouldForceRendering) {
-      this._updateThumbnailViewer();
-      this._forceRendering();
+      this.#updateThumbnailViewer();
+      this.#forceRendering();
     }
     if (isViewChanged) {
-      this._dispatchEvent();
+      this.#dispatchEvent();
     }
-    return isViewChanged;
   }
 
   open() {
@@ -261,12 +239,12 @@ class PDFSidebar {
     this.outerContainer.classList.add("sidebarMoving", "sidebarOpen");
 
     if (this.active === SidebarView.THUMBS) {
-      this._updateThumbnailViewer();
+      this.#updateThumbnailViewer();
     }
-    this._forceRendering();
-    this._dispatchEvent();
+    this.#forceRendering();
+    this.#dispatchEvent();
 
-    this._hideUINotification();
+    this.#hideUINotification();
   }
 
   close() {
@@ -280,8 +258,8 @@ class PDFSidebar {
     this.outerContainer.classList.add("sidebarMoving");
     this.outerContainer.classList.remove("sidebarOpen");
 
-    this._forceRendering();
-    this._dispatchEvent();
+    this.#forceRendering();
+    this.#dispatchEvent();
   }
 
   toggle() {
@@ -292,20 +270,18 @@ class PDFSidebar {
     }
   }
 
-  /**
-   * @private
-   */
-  _dispatchEvent() {
+  #dispatchEvent() {
+    if (this.isInitialViewSet && !this.isInitialEventDispatched) {
+      this.isInitialEventDispatched = true;
+    }
+
     this.eventBus.dispatch("sidebarviewchanged", {
       source: this,
       view: this.visibleView,
     });
   }
 
-  /**
-   * @private
-   */
-  _forceRendering() {
+  #forceRendering() {
     if (this.onToggled) {
       this.onToggled();
     } else {
@@ -315,10 +291,7 @@ class PDFSidebar {
     }
   }
 
-  /**
-   * @private
-   */
-  _updateThumbnailViewer() {
+  #updateThumbnailViewer() {
     const { pdfViewer, pdfThumbnailViewer } = this;
 
     // Use the rendered pages to set the corresponding thumbnail images.
@@ -333,10 +306,7 @@ class PDFSidebar {
     pdfThumbnailViewer.scrollThumbnailIntoView(pdfViewer.currentPageNumber);
   }
 
-  /**
-   * @private
-   */
-  _showUINotification() {
+  #showUINotification() {
     this.l10n.get("toggle_sidebar_notification2.title").then(msg => {
       this.toggleButton.title = msg;
     });
@@ -348,10 +318,7 @@ class PDFSidebar {
     }
   }
 
-  /**
-   * @private
-   */
-  _hideUINotification(reset = false) {
+  #hideUINotification(reset = false) {
     if (this.isOpen || reset) {
       // Only hide the notification on the `toggleButton` if the sidebar is
       // currently open, or when the current PDF document is being closed.
@@ -365,10 +332,7 @@ class PDFSidebar {
     }
   }
 
-  /**
-   * @private
-   */
-  _addEventListeners() {
+  #addEventListeners() {
     this.sidebarContainer.addEventListener("transitionend", evt => {
       if (evt.target === this.sidebarContainer) {
         this.outerContainer.classList.remove("sidebarMoving");
@@ -412,7 +376,7 @@ class PDFSidebar {
       button.disabled = !count;
 
       if (count) {
-        this._showUINotification();
+        this.#showUINotification();
       } else if (this.active === view) {
         // If the `view` was opened by the user during document load,
         // switch away from it if it turns out to be empty.
@@ -447,9 +411,9 @@ class PDFSidebar {
     this.eventBus._on("presentationmodechanged", evt => {
       if (
         evt.state === PresentationModeState.NORMAL &&
-        this.isThumbnailViewVisible
+        this.visibleView === SidebarView.THUMBS
       ) {
-        this._updateThumbnailViewer();
+        this.#updateThumbnailViewer();
       }
     });
   }