diff --git a/web/pdf_attachment_viewer.js b/web/pdf_attachment_viewer.js
index 529c77121..0ba8715ff 100644
--- a/web/pdf_attachment_viewer.js
+++ b/web/pdf_attachment_viewer.js
@@ -55,10 +55,14 @@ class PDFAttachmentViewer {
     this.container.textContent = "";
 
     if (!keepRenderedCapability) {
-      // NOTE: The *only* situation in which the `_renderedCapability` should
-      //       not be replaced is when appending file attachment annotations.
+      // The only situation in which the `_renderedCapability` should *not* be
+      // replaced is when appending FileAttachment annotations.
       this._renderedCapability = createPromiseCapability();
     }
+    if (this._pendingDispatchEvent) {
+      clearTimeout(this._pendingDispatchEvent);
+    }
+    this._pendingDispatchEvent = null;
   }
 
   /**
@@ -67,6 +71,25 @@ class PDFAttachmentViewer {
   _dispatchEvent(attachmentsCount) {
     this._renderedCapability.resolve();
 
+    if (this._pendingDispatchEvent) {
+      clearTimeout(this._pendingDispatchEvent);
+      this._pendingDispatchEvent = null;
+    }
+    if (attachmentsCount === 0) {
+      // Delay the event when no "regular" attachments exist, to allow time for
+      // parsing of any FileAttachment annotations that may be present on the
+      // *initially* rendered page; this reduces the likelihood of temporarily
+      // disabling the attachmentsView when the `PDFSidebar` handles the event.
+      this._pendingDispatchEvent = setTimeout(() => {
+        this.eventBus.dispatch("attachmentsloaded", {
+          source: this,
+          attachmentsCount: 0,
+        });
+        this._pendingDispatchEvent = null;
+      });
+      return;
+    }
+
     this.eventBus.dispatch("attachmentsloaded", {
       source: this,
       attachmentsCount,
@@ -129,23 +152,22 @@ class PDFAttachmentViewer {
    * @param {PDFAttachmentViewerRenderParameters} params
    */
   render({ attachments, keepRenderedCapability = false }) {
-    let attachmentsCount = 0;
-
     if (this.attachments) {
       this.reset(keepRenderedCapability === true);
     }
     this.attachments = attachments || null;
 
     if (!attachments) {
-      this._dispatchEvent(attachmentsCount);
+      this._dispatchEvent(/* attachmentsCount = */ 0);
       return;
     }
 
     const names = Object.keys(attachments).sort(function (a, b) {
       return a.toLowerCase().localeCompare(b.toLowerCase());
     });
-    attachmentsCount = names.length;
+    const attachmentsCount = names.length;
 
+    const fragment = document.createDocumentFragment();
     for (let i = 0; i < attachmentsCount; i++) {
       const item = attachments[names[i]];
       const filename = removeNullCharacters(getFilenameFromUrl(item.filename));
@@ -164,8 +186,9 @@ class PDFAttachmentViewer {
       }
 
       div.appendChild(button);
-      this.container.appendChild(div);
+      fragment.appendChild(div);
     }
+    this.container.appendChild(fragment);
 
     this._dispatchEvent(attachmentsCount);
   }
@@ -175,7 +198,12 @@ class PDFAttachmentViewer {
    * @private
    */
   _appendAttachment({ id, filename, content }) {
-    this._renderedCapability.promise.then(() => {
+    const renderedPromise = this._renderedCapability.promise;
+
+    renderedPromise.then(() => {
+      if (renderedPromise !== this._renderedCapability.promise) {
+        return; // The FileAttachment annotation belongs to a previous document.
+      }
       let attachments = this.attachments;
 
       if (!attachments) {
diff --git a/web/pdf_sidebar.js b/web/pdf_sidebar.js
index 9122d5d3c..512fbc850 100644
--- a/web/pdf_sidebar.js
+++ b/web/pdf_sidebar.js
@@ -445,31 +445,17 @@ class PDFSidebar {
     });
 
     this.eventBus._on("attachmentsloaded", evt => {
-      if (evt.attachmentsCount) {
-        this.attachmentsButton.disabled = false;
+      const attachmentsCount = evt.attachmentsCount;
 
+      this.attachmentsButton.disabled = !attachmentsCount;
+
+      if (attachmentsCount) {
         this._showUINotification(SidebarView.ATTACHMENTS);
-        return;
+      } else if (this.active === SidebarView.ATTACHMENTS) {
+        // If the attachments view was opened during document load, switch away
+        // from it if it turns out that the document has no attachments.
+        this.switchView(SidebarView.THUMBS);
       }
-
-      // Attempt to avoid temporarily disabling, and switching away from, the
-      // attachment view for documents that do not contain proper attachments
-      // but *only* FileAttachment annotations. Hence we defer those operations
-      // slightly to allow time for parsing any FileAttachment annotations that
-      // may be present on the *initially* rendered page of the document.
-      Promise.resolve().then(() => {
-        if (this.attachmentsView.hasChildNodes()) {
-          // FileAttachment annotations were appended to the attachment view.
-          return;
-        }
-        this.attachmentsButton.disabled = true;
-
-        if (this.active === SidebarView.ATTACHMENTS) {
-          // If the attachment view was opened during document load, switch away
-          // from it if it turns out that the document has no attachments.
-          this.switchView(SidebarView.THUMBS);
-        }
-      });
     });
 
     // Update the thumbnailViewer, if visible, when exiting presentation mode.