Content displays incorrectly when switching themes, such as wide or full-width

[BinaryMoon]

Issue Overview

If you switch between themes that support different gutenberg features then the content in the editor displays differently depending upon the theme. For example if you switch from a theme that supports full width content to a theme that doesn't then the editor will still display the content full width even though it won't display like this in the post.

In addition if you then edit the width setting (center an image for example) then there is no way to switch back to full width - which could be confusing to users. "Why can't I change it back to it's previous state?"

Steps to Reproduce (for bugs)

1. Enable a theme that supports wide images.
2. Create a new post with a full bleed image in it.
3. Switch to a theme that doesn't support wide images.
4. Edit the post you created in step 2. It will still be full bleed.

Expected Behavior

I imagine that if you are editing a post when running a theme that doesn't support full bleed content that the content will revert to the largest size supported by the theme. Essentially the full bleed setting is ignored. I also imagine that the setting would be kept - so that if you then switch back to a theme with full width support the image will go back to it's previous design.

[NewJenk]

Gutenberg styles would have to be theme-specific for it to be WYSIWYG so it would be up to theme authors to include Gutenberg styles.

If no Gutenberg styles are included with the theme then it would just be default Gutenberg that displays (so it wouldn't be WYSIWYG).

[BinaryMoon]

I'm not talking about the styles. I'm talking about the features and their use in the editor.

If you have a theme that has align-wide support, and then you switch to a theme that doesn't, then existing wide images will be displayed full width in the editor, but they won't be displayed full width on the post/ page. When you edit the image in the editor then you won't be able to make them full width again.

[NewJenk]

Hi @BinaryMoon,

Ah apologies - I get what you mean now.

[jeffpaul]

This ticket was mentioned in Slack in #core-editor by jeffpaul. View the logs.

[designsimply]

Closed #11259 to consolidate here and noting that the Media & Text block was specifically called out in that issue (in addition to a full bleed image mentioned here).

[paaljoachim]

Hey @BinaryMoon Ben. Can you recheck? I am doing a status check of the issue. Thanks.

[BinaryMoon]

It's still an issue but I don't think it's a big one. I'd be happy to close it.

[paaljoachim]

I am hoping a few people can take a closer look, and give some kind of knowledgable feedback.

@tellthemachines @jasmussen @gziolo
Thank you!

[tellthemachines]

I'm afraid there's no way to fix this on the editor side. Because users expect to be able to switch between themes and preserve their content settings, we can't remove the wide/full width classes and block attributes for a theme that doesn't happen to support them, and default editor styles provide a basic level of support for all alignments, so if those classes are set and the theme doesn't provide its own editor styles, the blocks will display as wide/full width in the editor.

The ideal solution is for themes that don't support wide/full width to provide editor styles that match their front end ones.

Closing the issue as there is nothing actionable here.