Describe the bug

In the "advanced Svelte tutorial", while being on the lesson svelte:window bindings
I noticed that, if the editor throws an error, for example after writing something invalid like:
console.log(foo); // foo is not defined
Then when I change to any of the other lessons, the background image deepsea.webp is still shown.

Reproduction

1. Visit the svelte window bindings lesson: https://svelte.dev/tutorial/svelte/svelte-window-bindings
2. Write something invalid in the editor like console.log(foo);
   
3. Change to another lesson, for example: https://svelte.dev/tutorial/svelte/svelte-body
   
4. The background image is still shown!

Logs

System Info

System:
    OS: Windows 10 10.0.19045
    CPU: (8) x64 Intel(R) Core(TM) i7-7820HQ CPU @ 2.90GHz
    Memory: 9.08 GB / 15.82 GB
  Binaries:
    Node: 22.12.0 - C:\Program Files\nodejs\node.EXE
    npm: 11.2.0 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Chromium (132.0.2957.115)
    Internet Explorer: 11.0.19041.4355

Severity

annoyance