From 3082604bdc03cfd8cee35e54dbb10caef956937e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Markb=C3=A5ge?= <sebastian@calyptus.eu>
Date: Thu, 24 Jul 2025 17:38:12 -0400
Subject: [PATCH] [DevTools] Feature detect sources panel (#33987)

I broke Firefox DevTools extension in #33968.

It turns out the Firefox has a placeholder object for the sources panel
which is empty. We need to detect the actual event handler.
---
 packages/react-devtools-extensions/src/main/index.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/react-devtools-extensions/src/main/index.js b/packages/react-devtools-extensions/src/main/index.js
index a82df1e226..46c42418c3 100644
--- a/packages/react-devtools-extensions/src/main/index.js
+++ b/packages/react-devtools-extensions/src/main/index.js
@@ -111,7 +111,7 @@ function createBridge() {
     chrome.devtools.panels.elements.onSelectionChanged.removeListener(
       onBrowserElementSelectionChanged,
     );
-    if (sourcesPanel) {
+    if (sourcesPanel && sourcesPanel.onSelectionChanged) {
       currentSelectedSource = null;
       sourcesPanel.onSelectionChanged.removeListener(
         onBrowserSourceSelectionChanged,
@@ -124,7 +124,7 @@ function createBridge() {
   chrome.devtools.panels.elements.onSelectionChanged.addListener(
     onBrowserElementSelectionChanged,
   );
-  if (sourcesPanel) {
+  if (sourcesPanel && sourcesPanel.onSelectionChanged) {
     sourcesPanel.onSelectionChanged.addListener(
       onBrowserSourceSelectionChanged,
     );