Test

customizer.php

<?php
/**
 * mwcc Theme Customizer
 *
 * @package mwcc
 */

if ( class_exists( 'WP_Customize_Control' ) ):
	class WP_Customize_Alert_Post_Control extends WP_Customize_Control {

		public $type = 'site_alert_post';
		public $post_type = 'alert';

		public function render_content() {
			$args = [
				'post_type' => $this->post_type,
				'post_status' => 'publish',
				'order_by' => 'title',
				'order' => 'ASC'
			];

			$alertPosts = new WP_Query( $args );

			if ( $alertPosts->have_posts() ): ?>
				<label>
					<span class="customize-control-title"><?= esc_html( $this->label ); ?></span>
					<select <?php $this->link(); ?>>
						<?php
				while ( $alertPosts->have_posts() ):
					$alertPosts->the_post();
					echo "<option " . selected( $this->value(), get_the_ID() ) . " value='" . get_the_ID() . "'>" . the_title( '', '', false ) . "</option>";
				endwhile;
				?>
					</select>
				</label>
				<?php
			endif;
			wp_reset_postdata();
		}
	}

	class WP_Customize_Testimonial_Post_Control extends WP_Customize_Control {

		public $type = 'home_testimonial';
		public $post_type = 'testimonial';

		public function render_content() {
			$args = [
				'post_type' => $this->post_type,
				'post_status' => 'publish',
				'order_by' => 'title',
				'order' => 'ASC'
			];

			$tPosts = new WP_Query( $args );

			if ( $tPosts->have_posts() ): ?>
				<label>
					<span class="customize-control-title"><?= esc_html( $this->label ); ?></span>
					<select <?php $this->link(); ?>>
						<?php
						while ( $tPosts->have_posts() ):
							$tPosts->the_post();
							echo "<option " . selected( $this->value(), get_the_ID() ) . " value='" . get_the_ID() . "'>" . the_title( '', '', false ) . "</option>";
						endwhile;
						?>
					</select>
				</label>
				<?php
			endif;
			wp_reset_postdata();
		}
	}

	class WP_Customize_Textbox_Control extends WP_Customize_Control {

		public $type = 'textarea';

		public function render_content() {
			?>
			<label>
				<span class="customize-control-title"><?php echo esc_html( $this->label ); ?></span>
				<textarea rows="5" style="width:100%;" <?php $this->link(); ?>><?php echo esc_textarea( $this->value() ); ?></textarea>
			</label>
			<?php
		}
	}
endif;

/**
 * Add postMessage support for site title and description for the Theme Customizer.
 *
 * @param WP_Customize_Manager $wp_customize Theme Customizer object.
 */
function mwcc_customize_register( $wp_customize ) {
	/**
	 * Remove section panels that we are not using on this site
	 */
	$wp_customize->remove_section( 'colors' );
	$wp_customize->remove_section( 'background_image' );
	$wp_customize->remove_section( 'static_front_page' );

	$wp_customize->get_setting( 'blogname' )->transport         = 'postMessage';
	$wp_customize->get_setting( 'blogdescription' )->transport  = 'postMessage';
	$wp_customize->get_setting( 'header_textcolor' )->transport = 'postMessage';

	$wp_customize->add_section( 'home_testimonial', [
		'title' => __( 'Testimonial', 'mwcc' ),
		'description' => __( 'Testimonial to display on home page', 'mwcc' ),
		'priority' => 102
	]);

	$wp_customize->add_setting( 'home_testimonial_post', [
		'capability' => 'edit_theme_options',
		'default' => '',
		'transport' => 'postMessage',
		'sanitize_callback' => function( $page_id, $setting ) {
			// Ensure $input is an absolute integer.
			$page_id = absint( $page_id );

			// If $page_id is an ID of a published page, return it; otherwise, return the default.
			return ( 'publish' == get_post_status( $page_id ) ? $page_id : $setting->default );
		}
	]);

	$wp_customize->add_control( new WP_Customize_Testimonial_Post_Control( $wp_customize, 'home_testimonial_poster', [
		'label' => esc_html__( 'Choose Testimonial', 'mwcc' ),
		'section' => 'home_testimonial',
		'settings' => 'home_testimonial_post',
		'post_type' => 'testimonial',
		'priority' => 12
	]));

	$wp_customize->add_section( 'footer_social', [
		'title' => __( 'Footer Social', 'mwcc' ),
		'description' => __( 'Social icons in footer', 'mwcc' ),
		'priority' => 101
	]);

	$wp_customize->add_setting( 'footer_social_settings', [
		'default' => '',
		'transport' => 'postMessage'
	]);

	$wp_customize->add_control( new WP_Customize_Textbox_Control( $wp_customize, 'footer_social_settings', [
		'label' => __( '', 'mwcc' ),
		'section' => 'footer_social',
		'settings' => 'footer_social_settings'
	]));

	$wp_customize->add_section( 'home_images', [
		'title' => __( 'Home Images', 'mwcc' ),
		'description' => __( 'Image row at top of home page', 'mwcc' ),
		'priority' => 100
	]);

	$wp_customize->add_setting( 'home_image_first', [
		'default' => '',
		'transport' => 'postMessage'
	]);

	$wp_customize->add_setting( 'home_image_first_link', [
		'default' => '',
		'transport' => 'postMessage'
	]);

	$wp_customize->add_setting( 'home_image_second', [
		'default' => '',
		'transport' => 'postMessage'
	]);

	$wp_customize->add_setting( 'home_image_second_link', [
		'default' => '',
		'transport' => 'postMessage'
	]);

	$wp_customize->add_setting( 'home_image_third', [
		'default' => '',
		'transport' => 'postMessage'
	]);

	$wp_customize->add_setting( 'home_image_third_link', [
		'default' => '',
		'transport' => 'postMessage'
	]);

	$wp_customize->add_control( new WP_Customize_Image_Control( $wp_customize, 'home_image_first', [
		'label' => 'First Image',
		'section' => 'home_images',
		'settings' => 'home_image_first'
	]));

	$wp_customize->add_control( new WP_Customize_Control( $wp_customize, 'home_images_first', [
		'label' => 'First Image Link',
		'section' => 'home_images',
		'settings' => 'home_image_first_link',
		'type' => 'text'
	]));

	$wp_customize->add_control( new WP_Customize_Image_Control( $wp_customize, 'home_image_second', [
		'label' => 'Second Image',
		'section' => 'home_images',
		'settings' => 'home_image_second'
	]));

	$wp_customize->add_control( new WP_Customize_Control( $wp_customize, 'home_images_second', [
		'label' => 'Second Image Link',
		'section' => 'home_images',
		'settings' => 'home_image_second_link',
		'type' => 'text'
	]));

	$wp_customize->add_control( new WP_Customize_Image_Control( $wp_customize, 'home_image_third', [
		'label' => 'Third Image',
		'section' => 'home_images',
		'settings' => 'home_image_third'
	]));

	$wp_customize->add_control( new WP_Customize_Control( $wp_customize, 'home_images_third', [
		'label' => 'Third Image Link',
		'section' => 'home_images',
		'settings' => 'home_image_third_link',
		'type' => 'text'
	]));

	$wp_customize->add_section( 'site_alert', [
		'title' => __( 'Site Alert', 'mwcc' ),
		'description' => __( 'Display alert at top of site', 'mwcc' ),
		'priority' => 101
	]);

	$wp_customize->add_setting( 'site_alert_show', [
		'default' => false,
		'transport' => 'postMessage',
		'sanitize_callback' => function( $input ) {
			return ( $input === true ) ? true : false;
		}
	]);

	$wp_customize->add_setting( 'site_alert_bgcolor', [
		'default' => '#fada0b',
		'transport' => 'postMessage',
		'sanitize_callback' => 'sanitize_hex_color',
	]);

	$wp_customize->add_setting( 'site_alert_post', [
		'capability' => 'edit_theme_options',
		'default' => '',
		'transport' => 'postMessage',
		'sanitize_callback' => function( $page_id, $setting ) {
			// Ensure $input is an absolute integer.
			$page_id = absint( $page_id );

			// If $page_id is an ID of a published page, return it; otherwise, return the default.
			return ( 'publish' == get_post_status( $page_id ) ? $page_id : $setting->default );
		}
	]);

	$wp_customize->add_control( new WP_Customize_Control( $wp_customize, 'site_alert', [
		'label' => esc_html__( 'Display Alert?', 'mwcc' ),
		'description' => esc_html__( 'Check to display site-wide alert message', 'mwcc' ),
		'section' => 'site_alert',
		'settings' => 'site_alert_show',
		'type' => 'checkbox',
		'priority' => 10
	]) );

	$wp_customize->add_control( new WP_Customize_Color_Control( $wp_customize, 'site_alert_bgcolor', [
		'label' => esc_html__( 'Background Color', 'mwcc' ),
		'description' => esc_html__( 'Background color to use', 'mwcc' ),
		'section' => 'site_alert',
		'settings' => 'site_alert_bgcolor',
		'priority' => 11
	]) );

	/*$wp_customize->add_control( new WP_Customize_Control( $wp_customize, 'site_alert_post', [
		'label' => esc_html__( 'Post?', 'mwcc' ),
		'description' => esc_html__( 'Post', 'mwcc' ),
		'section' => 'site_alert',
		'settings' => 'site_alert_post',
		'type' => 'dropdown-pages',
		'priority' => 12
	] ));*/
	$wp_customize->add_control( new WP_Customize_Alert_Post_Control( $wp_customize, 'site_alert_poster', [
		'label' => esc_html__( 'Choose Alert Page', 'mwcc' ),
		'section' => 'site_alert',
		'settings' => 'site_alert_post',
		'post_type' => 'alert',
		'priority' => 12
	]));
}
add_action( 'customize_register', 'mwcc_customize_register' );

/**
 * Binds JS handlers to make Theme Customizer preview reload changes asynchronously.
 */
function mwcc_customize_preview_js() {
	wp_enqueue_script( 'mwcc_customizer', get_stylesheet_directory_uri() . '/assets/scripts/vendor/customizer.js', array( 'customize-preview', 'wp-api' ), '20151215', true );
}
add_action( 'customize_preview_init', 'mwcc_customize_preview_js' );