Smart Snippets for WordPress – Part 2: Theme Tuning

Your functions.php file is more than just a catch-all—it’s a powerful way to fine-tune your theme’s behavior and the block editor experience without reaching for a plugin.

Here are some of my go-to snippets for theme-level control, helping you clean up the editor, register key features, and limit unwanted bloat.

🎨 1. Register Custom Navigation Menus

add_action('after_setup_theme', function() {
    register_nav_menus([
        'primary'   => 'Primary Menu',
        'footer'    => 'Footer Menu'
    ]);
});

Why use it: Allows you to assign menus in the Customizer or Site Editor. Needed for classic themes and some hybrid block builds.

🚫 2. Limit Available Block Types

add_filter('allowed_block_types_all', function($allowed_blocks, $editor_context) {
    return [
        'core/paragraph',
        'core/heading',
        'core/image',
        'core/columns',
        'core/buttons',
        'core/group'
    ];
}, 10, 2);

Why use it: Prevents clients from using blocks you don’t want in the layout—like Cover, Quote, or Pullquote. Keeps things focused.

✏️ 3. Add Custom Block Styles (e.g. Rounded Images)

register_block_style(
    'core/image',
    [
        'name'  => 'rounded',
        'label' => 'Rounded Image',
        'inline_style' => 'img { border-radius: 1rem; }'
    ]
);

Why use it: Let users apply custom visual styles to blocks (like rounded corners) without needing a class or plugin.

🧱 4. Disable Core Patterns (if you’re building your own)

remove_action('init', 'register_core_block_patterns');
remove_action('init', 'register_core_block_pattern_categories');

Why use it: Stops the editor from loading dozens of default patterns you don’t use. Makes your own patterns stand out.

🖌️ 5. Limit Editor Colors via theme.json

"settings": {
  "color": {
    "palette": [
      { "name": "Dark", "slug": "dark", "color": "#111" },
      { "name": "Accent", "slug": "accent", "color": "#f97316" }
    ]
  }
}

Why use it: Keeps your color usage consistent across blocks. Clients won’t go rogue with neon pink.

🧪 6. Add Custom Template Parts (for block themes)

add_action('init', function () {
    register_block_template_part(
        get_theme_file_path('parts/hero.html'),
        'theme',
        'header/hero',
        [
            'title' => 'Hero Section',
            'area'  => 'uncategorized'
        ]
    );
});

Why use it: Allows reusing template parts across block templates (header.html, home.html, etc.).

🧠 7. Add Global Editor Notice (Visual Alert for Clients)

add_action('enqueue_block_editor_assets', function () {
    echo '<style>.edit-post-header:after {
        content: "⚠️ Remember to save template changes!";
        color: #d6336c;
        font-weight: bold;
        margin-left: 2rem;
    }</style>';
});

Why use it: Great for reminding clients to click “Save” in FSE. Adds visual cues inside the editor header.

🔒 8. Lock Specific Blocks or Regions (Block Locking)

add_filter('block_editor_settings_all', function ($settings) {
    $settings['canLockBlocks'] = true;
    return $settings;
});

Why use it: Enables the UI for block locking (prevent moving/removing critical layout blocks). Works well with patterns and FSE templates.

🧼 9. Remove Unused Block Styles (Like Button Variants)

add_action('init', function () {
    wp_deregister_style('wp-block-button');
});

Why use it: Cleans up default button styles you might be replacing with your own SCSS. Helps reduce CSS bloat.

🧭 Final Thoughts

These are the kind of customizations I build into nearly every child theme or plugin-powered layout. They keep the editing experience tight, intuitive, and aligned with the actual front-end.

They also prevent surprises—especially when handing off a site to clients or managing content at scale.