tor-browser

commit c3503f7d195f367cd0e0826305f4653414c70346
parent 0f032496e6e0d0ee09a0463b7c0e0dcdf8aef0d9
Author: Emma Zuehlcke <emz@mozilla.com>
Date:   Wed,  8 Oct 2025 13:38:22 +0000

Bug 1966696 - Prevent setPointerCapture for SmartBlock embed placeholders. r=webcompat-reviewers,twisniewski

Differential Revision: https://phabricator.services.mozilla.com/D263935

Diffstat:
M
browser/extensions/webcompat/lib/smartblock_embeds_helper.js
 | 
31
++++++++++++++++++++++++++++++-

1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/browser/extensions/webcompat/lib/smartblock_embeds_helper.js b/browser/extensions/webcompat/lib/smartblock_embeds_helper.js
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/* globals browser */
+/* globals browser exportFunction */
 
 "use strict";
 
@@ -156,6 +156,10 @@ const embedHelperLib = (() => {
       // Create the placeholder inside a shadow dom
       const placeholderDiv = document.createElement("div");
 
+      // Workaround to make sure clicks reach our placeholder button if the site
+      // uses pointer capture. See Bug 1966696 for an example.
+      disableSetPointerCaptureFor(placeholderDiv);
+
       if (isTestShim) {
         // Tag the div with a class to make it easily detectable FOR THE TEST SHIM ONLY
         placeholderDiv.classList.add("shimmed-embedded-content");
@@ -255,6 +259,31 @@ const embedHelperLib = (() => {
   }
 
   /**
+   * Disables the setPointerCapture method for a given element to prevent
+   * pointer capture issues.
+   *
+   * @param {HTMLElement} el - The element to disable setPointerCapture for.
+   */
+  function disableSetPointerCaptureFor(el) {
+    const pageEl = el.wrappedJSObject;
+
+    Object.defineProperty(pageEl, "setPointerCapture", {
+      configurable: true,
+      writable: true,
+      enumerable: false,
+      // no-op ONLY for this element
+      value: exportFunction(function (_pointerId) {
+        console.warn(
+          "Blocked setPointerCapture on SmartBlock embed placeholder.",
+          this,
+          _pointerId
+        );
+        // swallow
+      }, window),
+    });
+  }
+
+  /**
    * Initializes a smartblock embeds shim on the page.
    *
    * @param {object} SHIM_INFO - Information about the shim wrapped in an object.