'use the block API's style' warning for CSS loaded by 'admin_enqueue_scripts'.

[ddryo]

Description

CSS that is not for a specific block but for the UI of the admin and editor are loaded using the 'admin_enqueue_scripts' and 'enqueue_block_editor_assets' hooks.

Then, when the device preview is toggled or the block style preview is opened, those CSS are loaded in the <iframe>, and the "use the block API's style" warning appears as shown below.

This may be related to issue #34333.

I feel something like the following is needed.

• Stop loading these CSS into the iframe and create a more suitable hook that will load the CSS into the iframe.
• Or, I think you need to implement a way to detect loading in an iframe within the 'admin_enqueue_scripts' hook. (If there is one already, please let me know, I can't detect it with IFRAME_REQUEST)

Step-by-step reproduction instructions

1. Use the 'admin_enqueue_scripts' and 'enqueue_block_editor_assets' hooks to load the CSS.

2. In the block editor, set the 'Preview' mode to 'Tablet' or 'Mobile

3. Then you will see a warning in the console.

Environment info

• WordPress 5.9-RC2

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

[aristath]

These warnings were already removed in #37937 and the change will be backported to WP5.9 👍
Closing this one as it has been resolved