Custom CSS cannot be used with original blocks lacking block.json #75766

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1. nendeb

   added

   [Type] BugAn existing feature does not function as intendedAn existing feature does not function as intended

   on Feb 20, 2026
2. Mamaduka

   added

   Global StylesAnything related to the broader Global Styles efforts, including Styles Engine and theme.jsonAnything related to the broader Global Styles efforts, including Styles Engine and theme.json

   on Feb 20, 2026
3. Mamaduka commented on Feb 20, 2026

   

   Mamaduka

   on Feb 20, 2026

   Last edited by Mamaduka

   Member

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   cc @glendaviesnz

   @nendeb, can you share an example block? While block.json is nice to have, it's not required, and the same configuration can be done via PHP.
4. Mamaduka

   added this to WordPress 7.0 Editor Taskson Feb 20, 2026
5. Mamaduka

   moved this to ❓ Triage in WordPress 7.0 Editor Taskson Feb 20, 2026
6. Mamaduka

   added

   [Status] Needs More InfoFollow-up required in order to be actionable.Follow-up required in order to be actionable.

   on Feb 20, 2026
7. nendeb commented on Feb 20, 2026

   

   nendeb

   on Feb 20, 2026

   Author

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   cc@glendaviesnz
   Thank you.

   I'm sorry, but there are no blocks I can share.
   What we currently know is
   the case where block.json is not used with server-side rendering.

   Also, adding

       style: {
           type: ‘object’,
       },
   

   to the attributes makes it display correctly, but I'm not sure if this is correct.

   As I mentioned earlier, I believe it is undesirable to force existing blocks that have been functioning normally to be modified simply because they lack a block.json file.

   Please consider how to address this.
8. t-hamano commented on Feb 21, 2026

   

   t-hamano

   on Feb 21, 2026

   Contributor

   More actions

   The underlying problem doesn't seem to be related to block.json. Perhaps the results differ depending on whether or not the attributes.style object is present.

   Try these steps:

   1. Run the code in your browser console and register the custom block.
   2. Insert the block into a post.
   3. Add custom CSS.
   4. Open your code editor.
   5. Verify that the custom CSS data is present.

   The following code does not work with custom CSS:

   wp.blocks.registerBlockType('my-plugin/my-custom-block', {
   	apiVersion: 3,
   	title: 'Custom Block',
   	edit: function () {
   		return wp.element.createElement(
   			'p',
   			wp.blockEditor.useBlockProps(),
   			'Hello World'
   		);
   	},
   });

   The following code works with custom CSS:

   wp.blocks.registerBlockType('my-plugin/my-custom-block', {
   	apiVersion: 3,
   	title: 'Custom Block with color support',
   	supports: {
   		color: {
   			text: true
   		}
   	},
   	edit: function () {
   		return wp.element.createElement(
   			'p',
   			wp.blockEditor.useBlockProps(),
   			'Hello World'
   		);
   	},
   });

   wp.blocks.registerBlockType('my-plugin/my-custom-block', {
   	apiVersion: 3,
   	title: 'Custom Block with style object',
   	attributes: {
   		style: {}
   	},
   	edit: function () {
   		return wp.element.createElement(
   			'p',
   			wp.blockEditor.useBlockProps(),
   			'Hello World'
   		);
   	},
   });

   Please consider either providing backward compatibility support or disabling customCSS entirely.

   Custom CSS support can be disabled.

   wp.blocks.registerBlockType('my-plugin/my-custom-block', {
   	apiVersion: 3,
   	title: 'Block without custom CSS support',
   	supports: {
   		customCSS: false
   	},
   	edit: function () {
   		return wp.element.createElement(
   			'p',
   			wp.blockEditor.useBlockProps(),
   			'Hello World'
   		);
   	},
   });
9. github-actions

   assigned

   t-hamano

   on Feb 21, 2026
10. github-actions

    added

    [Status] In ProgressTracking issues with work in progressTracking issues with work in progress

    on Feb 21, 2026
11. t-hamano

    moved this from ❓ Triage to 🏗️ In Progress in WordPress 7.0 Editor Taskson Feb 21, 2026
12. nendeb commented on Feb 21, 2026

    

    nendeb

    on Feb 21, 2026

    Author

    More actions

    t-hamano

    Thank you.

    attributes: {style: {}},
    supports: {color: {text: true},

    Both have been verified to work.
    I don't understand why adding color makes it work, but since it seems you're accommodating this as backward compatibility as requested, I appreciate it.
13. t-hamano

    closed this as completedin #75797on Feb 24, 2026
14. github-project-automation

    moved this from 🏗️ In Progress to ✅ Done in WordPress 7.0 Editor Taskson Feb 24, 2026