From 2d5ed8634ff21c8b8e3cf708176d268428867c6d Mon Sep 17 00:00:00 2001
From: Joey Arhar <jarhar@chromium.org>
Date: Wed, 2 Apr 2025 11:52:09 -0700
Subject: [PATCH] Don't run light dismiss on right click

This fixes a bug where showing a popover during the contextmenu event
handler immediately gets light dismissed as soon as the user lifts up on
the mouse button because the contextmenu event is fired in between
pointerdown and pointerup.

Fixes https://github.com/whatwg/html/issues/10905
---
 source | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/source b/source
index 2f6d690e48d..b0b73bfe9c8 100644
--- a/source
+++ b/source
@@ -3359,6 +3359,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
     <ul class="brief">
      <li>The <dfn data-x-href="https://w3c.github.io/uievents/#mouseevent"><code>MouseEvent</code></dfn> interface</li>
      <li>The <code>MouseEvent</code> interface's <dfn data-x="dom-MouseEvent-relatedTarget" data-x-href="https://w3c.github.io/uievents/#dom-mouseevent-relatedtarget"><code>relatedTarget</code></dfn> attribute</li>
+     <li>The <code>MouseEvent</code> interface's <dfn data-x="dom-MouseEvent-button" data-x-href="https://w3c.github.io/uievents/#dom-mouseevent-button"><code>button</code></dfn> attribute</li>
      <li><dfn data-x-href="https://w3c.github.io/uievents/#dictdef-mouseeventinit"><code>MouseEventInit</code></dfn> dictionary type</li>
 
      <li>The <dfn data-x-href="https://w3c.github.io/uievents/#focusevent"><code>FocusEvent</code></dfn> interface</li>
@@ -62433,6 +62434,9 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
   <var>event</var>:</p>
 
   <ol>
+   <li><p>If <var>event</var>'s <code data-x="dom-MouseEvent-button">button</code> is not 0, then
+   return.</p></li>
+
    <li><p>Run <span>light dismiss open popovers</span> with <var>event</var>.</p></li>
 
    <li><p>Run <span>light dismiss open dialogs</span> with <var>event</var>.</p></li>