WordPress: Restrict the Customizer menu search to titles

functions.php

/**
 * Restrict Customizer menu search to titles
 * Based on: https://stackoverflow.com/questions/54155517/how-to-limit-wp-admin-to-search-only-titles
 * Added Customizer screen detection
 */
add_filter(
	'posts_search',
	function( $search, $wp_query ) {
		global $wp_customize;
		global $wpdb;

		// leave if we are not in the admin customizer
		if ( ! is_admin() || ! isset( $wp_customize ) || empty( $search ) ) {
			return $search;
		}
		
		$q         = $wp_query->query_vars;
		$x         = ! empty( $q['exact'] ) ? '' : '%';
		$search    = '';
		$searchand = '';
		foreach ( (array) $q['search_terms'] as $term ) {
			$term      = esc_sql( $wpdb->esc_like( $term ) );
			$search   .= "{$searchand}($wpdb->posts.post_title LIKE '{$x}{$term}{$x}')";
			$searchand = ' AND ';
		}
		if ( ! empty( $search ) ) {
			$search = " AND ({$search}) ";
		}
		return $search;
	},
	10,
	2
);