From 72011c5088e277b555212acb90b7b90818bb2f1f Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Sun, 26 Apr 2026 14:33:47 +0200
Subject: [PATCH] Get the `zIndex` correctly in
 `PopupElement.prototype.renderCommentButton`

In practice this probably hasn't caused any bugs, however given that `DOMElement.style.zIndex` returns a string the existing code is subtly wrong.
This is also consistent with pre-existing `zIndex` code in the `PopupElement` class, see the `#show` and `#hide` methods.
---
 src/display/annotation_layer.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/display/annotation_layer.js b/src/display/annotation_layer.js
index 8206d3f7b..59cc9dfcb 100644
--- a/src/display/annotation_layer.js
+++ b/src/display/annotation_layer.js
@@ -2596,7 +2596,7 @@ class PopupElement {
       const button = (this.#commentButton = document.createElement("button"));
       button.className = "annotationCommentButton";
       const parentContainer = this.#firstElement.container;
-      button.style.zIndex = parentContainer.style.zIndex + 1;
+      button.style.zIndex = parseInt(parentContainer.style.zIndex, 10) + 1;
       button.tabIndex = 0;
       button.ariaHasPopup = "dialog";
       button.ariaControls = "commentPopup";
@@ -3778,6 +3778,8 @@ class AnnotationLayer {
 
   #hasAriaAttributesFromStructTree = false;
 
+  zIndex = 0;
+
   constructor({
     div,
     accessibilityManager,
@@ -3798,7 +3800,6 @@ class AnnotationLayer {
     this.#annotationStorage = annotationStorage || new AnnotationStorage();
     this.page = page;
     this.viewport = viewport;
-    this.zIndex = 0;
     this._annotationEditorUIManager = annotationEditorUIManager;
     this._commentManager = commentManager || null;