Title: Error when adding Additional CSS Class(es) to the Gutenberg block
Last modified: June 29, 2019

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# Error when adding Additional CSS Class(es) to the Gutenberg block

 *  Resolved [Marco Almeida | Webdados](https://wordpress.org/support/users/webdados/)
 * (@webdados)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/error-when-adding-additional-css-classes-to-the-gutenberg-block/)
 * When we add an class on Block > Advanced > Additional CSS Class we get this error:
 * “This block contains unexpected or invalid content.”
 * [https://snag.gy/xa8lr2.jpg](https://snag.gy/xa8lr2.jpg)

Viewing 5 replies - 1 through 5 (of 5 total)

 *  [Kevin Batdorf](https://wordpress.org/support/users/kbat82/)
 * (@kbat82)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/error-when-adding-additional-css-classes-to-the-gutenberg-block/#post-11684704)
 * Hi [@webdados](https://wordpress.org/support/users/webdados/)
 * I’m not getting that and the code in your screenshot looks okay.
 * What version of WP are you using?
    Does it happen every time, or just once? There’s
   a chance another plugin is causing a conflict. Are you able to try with other
   plugins disabled?
 *  [Kevin Batdorf](https://wordpress.org/support/users/kbat82/)
 * (@kbat82)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/error-when-adding-additional-css-classes-to-the-gutenberg-block/#post-11684707)
 * Hi [@webdados](https://wordpress.org/support/users/webdados/)
 * Nevermind, I just updated to the latest WP dev branch and I get the error. I’ll
   follow up on Monday about this.
 *  Thread Starter [Marco Almeida | Webdados](https://wordpress.org/support/users/webdados/)
 * (@webdados)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/error-when-adding-additional-css-classes-to-the-gutenberg-block/#post-11684724)
 * I got the Gutenberg plugin installed, so maybe it’s something still not on the
   WP core (but that will be soon).
 * Thanks for your quick reply. I’ll use a shortcode in the meanwhile.
 *  [Kevin Batdorf](https://wordpress.org/support/users/kbat82/)
 * (@kbat82)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/error-when-adding-additional-css-classes-to-the-gutenberg-block/#post-11695501)
 * Hi [@webdados](https://wordpress.org/support/users/webdados/)
 * I have this fixed and will be out with the next release. Sorry for the inconvenience.
 *  Thread Starter [Marco Almeida | Webdados](https://wordpress.org/support/users/webdados/)
 * (@webdados)
 * [6 years, 11 months ago](https://wordpress.org/support/topic/error-when-adding-additional-css-classes-to-the-gutenberg-block/#post-11695503)
 * \o/

Viewing 5 replies - 1 through 5 (of 5 total)

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 * 5 replies
 * 2 participants
 * Last reply from: [Marco Almeida | Webdados](https://wordpress.org/support/users/webdados/)
 * Last activity: [6 years, 11 months ago](https://wordpress.org/support/topic/error-when-adding-additional-css-classes-to-the-gutenberg-block/#post-11695503)
 * Status: resolved