Previewing email templates in admin loads admin area CSS

[erfanimani]

Preconditions (*)

1. Magento 2.3.4, but this happens to other versions too

Steps to reproduce (*)

1. In the admin, navigate to Marketing -> Email Templates
2. Load a template and hit Preview Template

Expected result (*)

1. Email looks as "true" as possible, without any interference of CSS unrelated to the actual email

Actual result (*)

1. Admin CSS interferes with how the email looks

The issue is simply that admin CSS is loaded when previewing email templates, which could interfere with how the emails show up as. With the Luma emails this difference is not much, some minor typography changes. However, when designing email templates from scratch, this could have a big effect — making the Preview Template functionality useless.

See screenshot below. Essentially there are two pages, one is the outer page (preview), and one is the inner page/iframe (popup). The iframe exists supposedly to isolate CSS changes. However, that's rendered moot as admin CSS is also loaded inside the iframe.

[m2-assistant]

Hi @erfanimani. Thank you for your report.
To help us process this issue please make sure that you provided the following information:

• Summary of the issue
• Information on your environment
• Steps to reproduce
• Expected and actual results

Please make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce. To deploy vanilla Magento instance on our environment, please, add a comment to the issue:

@magento give me 2.4-develop instance - upcoming 2.4.x release

For more details, please, review the Magento Contributor Assistant documentation.

@erfanimani do you confirm that you were able to reproduce the issue on vanilla Magento instance following steps to reproduce?

• yes
• no

---

• Join Magento Community Engineering Slack and ask your questions in #github channel.

[slavvka]

Hi @erfanimani. Thank you for your report.
The issue has been fixed in #27828 by @mrtuvn in 2.4-develop branch
Related commit(s):

• d7cf1881141fd855ff79f611a31ea2570726bdc3
• 77a4e8c44e1ee901d77aa8d6680fcd5365cd376d
• 6b8fc4c55272229164fde82ddbd631f771f302d7
• facbe37f9f51eb315bc5da1fb3c5000d743057ff
• 1ef8a517089ff132a7bb526194999ae83247ce50
• cd961c4444d60a4a2efdbd711485904d39d9a04d
• bcef3f5339b359e195d447f09ee14a2eea140f60
• 8aeffcc289e8bc62b4d97bb7ef816f0de876857b
• 461eab38f0a2945bda7fcc232e632076b38f5a68
• 84f424c98d20d1263519f6e2948670368d807861

The fix will be available with the upcoming 2.4.0 release.

[magento-engcom-team]

Based on the provided information internal tickets MC-34531 were created.