# Frozen material behaves differently in playwright test

**URL:** <https://forum.babylonjs.com/t/frozen-material-behaves-differently-in-playwright-test/60421>\
**Category:** Bugs\
**Tags:** material\
**Created:** [September 9, 2025, 6:58am UTC](https://forum.babylonjs.com/t/frozen-material-behaves-differently-in-playwright-test/60421 "2025-09-09T06:58:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![fazil47](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/fazil47/32/38879_2.png) [@fazil47](https://forum.babylonjs.com/u/fazil47)\
**Post date:** [September 9, 2025, 6:58am UTC](https://forum.babylonjs.com/t/frozen-material-behaves-differently-in-playwright-test/60421/1 "2025-09-09T06:58:03Z")

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[repro.zip](https://forum.babylonjs.com/uploads/short-url/x1ZhOk5aDStCHwUD7yrKrpCw0UV.zip) (8.5 KB)

Steps to reproduce:

1. Install dependencies
2. Debug the “Babylon.js scene” testcase
3. In the test browser window console, set the material alpha like this:  
`scene.getMaterialByName(“alphaMat”).alpha = 0.6`
4. Mark the material as dirty to see the change:  
`scene.getMaterialByName(“alphaMat”).markDirty(true)`

What is confusing is that step 4 isn’t necessary when you do it in a normal Chrome browser (or even when you open a new window in the same Chromium instance playwright is controlling). Why is there a difference?

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<div class="post-metadata">

**Author:** ![sebavan](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/sebavan/32/57_2.png) [@sebavan](https://forum.babylonjs.com/u/sebavan)\
**Post date:** [September 9, 2025, 3:55pm UTC](https://forum.babylonjs.com/t/frozen-material-behaves-differently-in-playwright-test/60421/2 "2025-09-09T15:55:02Z")

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I think it is more a playwright question on their infra as their should not be a difference. Maybe check with Claude as well ?