Adjacent sibling selector does not work in querySelector, when <select> element is involved.

[ushi-as]

Describe the bug

Since version 15 of happy-dom i see strange behavior when using the adjacent sibling selector (+), when a select element is involved. When selecting 'E1 + E2', happy-dom does not find E2 if E1 is a <select> Element.

To Reproduce

Execute the following script:

import { Window } from 'happy-dom';

const window = new Window({ url: 'https://localhost:8080' });
const document = window.document;

document.body.innerHTML = `
<div class="a"></div>
<div class="b"></div>
`

console.log(document.body.innerHTML);
console.log(document.body.querySelector('.a + .b') !== null);
console.log(document.body.querySelector('div + div') !== null);

document.body.innerHTML = `
<select class="a"></select>
<div class="b"></div>
`

console.log(document.body.innerHTML);
console.log(document.body.querySelector('.a + .b') !== null);
console.log(document.body.querySelector('select + div') !== null);

document.body.innerHTML = `
<div class="a"></div>
<select class="b"></select>
`

console.log(document.body.innerHTML);
console.log(document.body.querySelector('.a + .b') !== null);
console.log(document.body.querySelector('div + select') !== null);

It outputs:

<div class="a"></div>
<div class="b"></div>

true
true

<select class="a"></select>
<div class="b"></div>

false
false

<div class="a"></div>
<select class="b"></select>

true
true

Expected behavior

The expected output is:

<div class="a"></div>
<div class="b"></div>

true
true

<select class="a"></select>
<div class="b"></div>

true
true

<div class="a"></div>
<select class="b"></select>

true
true

Device:

• Node version: 20
• happy-dom version: 15.7