Style Book: Inconsistent preview of Custom HTML widget between styles variations

[franzaurus]

Description

When browsing through the style variations of a block theme, the Custom HTML widget preview on the Style Book is displayed inconsistently. This is because the background of the currently active style variation is carried over to other style variations.

This issue affected WP 6.2 Beta 2 and Gutenberg 15.1.1 as well.

I've checked #9129 but it is not related.

Step-by-step reproduction instructions

1. Activate a block theme (TT3 or other)
2. Select a style variation
3. Go to its Style Book
4. Scroll through the Custom HTML widget
5. While staying in the Style Book, browse through a few more style variations
6. Observe the Custom HTML’s background preview doesn’t follow the changing styles

Screenshots, screen recording, code snippet

On WP 6.2 Beta 2

On Gutenberg 15.1.1

Environment info

• WP Core 6.2 Beta 2
• Gutenberg 15.1.1
• Firefox 111.0b1
• Chrome 109.0.5414.120
• TT3 & Beaumont themes.

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[franzaurus]

It might be related to #46758

[Mamaduka]

Hi, @franzaurus

Are you still able to reproduce the issue with WP 6.2 beta 4?

[franzaurus]

Hello, @Mamaduka. The issue can still be reproduced in WP 6.2 beta 5.