Cover Block: Positioning regression

[sirreal]

Description

Cover block has a visual regression in 9.8 RC1 with positioning in the editor.

Expected (9.7)

Actual (9.8 RC1)

Step-by-step reproduction instructions

1. Use Gutenberg 9.8 RC1
2. Add a Cover block
3. Change the background position
4. Observe the visual regression

WordPress information

• WordPress version: 5.6
• Gutenberg version: 9.8.0-rc.1
• Are all plugins except Gutenberg deactivated? yes
• Are you using a default theme (e.g. Twenty Twenty-One)? yes

[sirreal]

CC @ajlende May be related to #25171

[sirreal]

The issue is not limited to the editor. See the published post:

Expected (9.7)

Actual (9.8 RC1)

[jasmussen]

I recall a very recent PR that removed a height: 100%; value from cover, that seems potentially related. I can't recall which PR, but I recall pinging @senadir, do you recall and/or think this might be related?

[ockham]

I recall a very recent PR that removed a height: 100%; value from cover, that seems potentially related. I can't recall which PR,

@jasmussen This one? #28114

[jasmussen]

That's the one! Thank you. I've reproduced an issue:

Adding back height: 100%; fixes it, but so does overflow: hidden;, so I'm going to try a PR with that.

[jasmussen]

I believe that #28287 fixes this issue. I'm not completely sure, so would appreciate your eyes!