Visual Composer Extension

<?php
/*

Extends Visual Composer 

More information can be found here: http://kb.wpbakery.com/index.php?title=Category:Visual_Composer

*/

// don't load directly
if (!defined('ABSPATH')) die('-1');

class VCExtendAddonClass {

    function __construct() {
        // We safely integrate with VC with this hook
        add_action( 'init', array( $this, 'integrateWithVC' ) );

        // Register CSS and JS
        add_action( 'wp_enqueue_scripts', array( $this, 'loadCssAndJs' ) );
    }
 
    public function integrateWithVC() {

        // Check if Visual Composer is installed
        if ( ! defined( 'WPB_VC_VERSION' ) ) {
            // Display notice that Visual Compser is required
            add_action('admin_notices', array( $this, 'showVcVersionNotice' ));
            return;
        }
 
        /*
        Add your Visual Composer logic here.
        Lets call vc_map function to "register" our custom shortcode within Visual Composer interface.

        More info: http://kb.wpbakery.com/index.php?title=Vc_map
        */

        /**
         * Add Post Content Shortcode
         * https://wordpress.org/plugins/post-content-shortcodes/
         */
        vc_map( array(

            "name" => __("Post Content [Single]", 'vc_extend'),
            "description" => __("Add the content from another post", 'vc_extend'),
            "base" => "post_content",
            "class" => "post_content",
            "controls" => "full",
            "content_element" => true,
            "show_settings_on_create" => true,
            "icon" => '', // or css class name which you can reffer in your css file later. Example: "vc_extend_my_class"
            "category" => __('Content', 'js_composer'),
            //'admin_enqueue_js' => array(plugins_url('assets/vc_extend.js', __FILE__)), // This will load js file in the VC backend editor
            'admin_enqueue_css' => array(get_stylesheet_directory_uri() . '/assets/css/vc_extend_admin.min.css'), // This will load css file in the VC backend editor
            "params" => array(

                array(
                  "type" => "textfield",
                  "holder" => "div",
                  "class" => "",
                  "heading" => __("Post ID"),
                  "param_name" => "id",
                  "admin_label" => true,
                  "value" => "",
                  "description" => __("the ID of the post you want to include")
               ),

                array(
                  "type" => "checkbox",
                  "holder" => "div",
                  "class" => "",
                  "heading" => __("Show title"),
                  "param_name" => "show_title",
                  "admin_label" => true,
                  "value" =>  array( 'Yes please' => 1),
                  "description" => __("Whether to show the post title")
               ),

                array(
                  "type" => "checkbox",
                  "holder" => "div",
                  "class" => "",
                  "heading" => __("Process shortcodes"),
                  "param_name" => "shortcodes",
                  "admin_label" => true,
                  "value" =>  array( 'Yes please' => 1),
                  "description" => __("Whether to process the shorcodes taht the post may contain")
               )

            )

        ) );

    }

    /*
    Load plugin css and javascript files which you may need on front end of your site
    */
    public function loadCssAndJs() {

      // wp_register_style( 'vc_extend_style', plugins_url('assets/vc_extend.css', __FILE__) );
      // wp_enqueue_style( 'vc_extend_style' );

      // If you need any javascript files on front end, here is how you can load them.
      // wp_enqueue_script( 'vc_extend_js', plugins_url('assets/vc_extend.js', __FILE__), array('jquery') );
    }

    /*
    Show notice if your plugin is activated but Visual Composer is not
    */
    public function showVcVersionNotice() {
        $plugin_data = get_plugin_data(__FILE__);
        echo '
        <div class="updated">
          <p>'.sprintf(__('<strong>%s</strong> requires <strong><a href="http://bit.ly/vcomposer" target="_blank">Visual Composer</a></strong> plugin to be installed and activated on your site.', 'vc_extend'), $plugin_data['Name']).'</p>
        </div>';
    }
}
// Finally initialize code
new VCExtendAddonClass();


if ( class_exists( 'WPBakeryShortCode' ) ) {

    class WPBakeryShortCode_post_content extends WPBakeryShortCode {

      public function contentAdmin( $atts, $content = null ) {

        return parent::contentAdmin( $atts, $content );

      }

      protected function outputTitle( $title ) {
        return '<h4 class="wpb_element_title">My Shortcode title [testing]</h4>';
      }

    }

}

For some reason this plugin affects the theme font and color. Occured after updating WordPress and the theme. Current version of my WP is 4.0.

EDIT:

Getting the following error to console, if pkugin installed: The stylesheet /dev/?load=custom-style.css&post_id=2&ver=4.0 was not loaded because its MIME type, "text/html", is not "text/css".