Updating to WordPress 5.6 for Blocks Based Theme Fix

I have a block-based theme using Gutenberg editor. After updating to WordPress 5.6 the editor window with a collection of full width blocks was pushing the sidebar out of editor page margins.

I’ve noticed the class .interface-interface-skeleton__editor is getting too wide on admin screen. I guess wide and full-width blocks are pushing it.

Adding max-width: 100%; is fixing the problem.

Since I use ACF Pro anyway, I’m adding this to functions.php of the theme:

// add some styles to ACF
add_action( 'acf/input/admin_footer', 'add_to_acf_styles' );
function add_to_acf_styles() { ?>
    <style>
        .interface-interface-skeleton__editor {
            max-width: 100%;
        }
    </style>
    <?php
}

It’s fixing the editor overflow of wide blocks.

Here you may read more on the issue.