From 5610f3e68803037ed99f6786dc9709c527739b1e Mon Sep 17 00:00:00 2001
From: Birk Skyum <birk.skyum@pm.me>
Date: Sun, 26 Jul 2026 01:42:10 +0200
Subject: [PATCH] Stop the dev toolbar from reporting benign `ResizeObserver
 loop` notifications as application errors.

---
 .changeset/tricky-goats-cheer.md                | 5 +++++
 packages/start/src/shared/dev-toolbar/index.tsx | 5 +++++
 2 files changed, 10 insertions(+)
 create mode 100644 .changeset/tricky-goats-cheer.md

diff --git a/.changeset/tricky-goats-cheer.md b/.changeset/tricky-goats-cheer.md
new file mode 100644
index 000000000..e02ac9eb3
--- /dev/null
+++ b/.changeset/tricky-goats-cheer.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/start": patch
+---
+
+Stop the dev toolbar from reporting benign `ResizeObserver loop` notifications as application errors. Browsers dispatch these as window `error` events carrying no error object, so the toolbar was capturing the raw `ErrorEvent` and force-opening the error panel over the app on every resize.
diff --git a/packages/start/src/shared/dev-toolbar/index.tsx b/packages/start/src/shared/dev-toolbar/index.tsx
index 7bfa72ef0..e26c8c10a 100644
--- a/packages/start/src/shared/dev-toolbar/index.tsx
+++ b/packages/start/src/shared/dev-toolbar/index.tsx
@@ -157,6 +157,11 @@ export function DevToolbar(props: DevToolbarProps) {
 
   createEffect(() => {
     const onErrorEvent = (error: ErrorEvent) => {
+      // Browsers dispatch benign ResizeObserver loop notifications as window
+      // "error" events carrying no error object. They aren't app errors.
+      if (!error.error && error.message?.startsWith("ResizeObserver loop")) {
+        return;
+      }
       pushError(error.error ?? error);
     };