Visual Composer; custom elements won't load textarea_html/'content' - wordpress

Question

Currently using WordPress 4.4.2, I'm in the process of developing some custom Visual Composer elements.
It seems (however), that whenever I want to use a textarea_html param (So the end-user can use the wysiwyg editor) I cannot seem to grab it's contents when rendering the template.
Contents of 'titled_content_box.php'
// called during vc_before_init
function integrate_titled_content_box(){
register_titled_content_box();
add_shortcode( 'titled_content_box', 'titled_content_box_func');
}
//Mapping of titled-contentbox
function register_titled_content_box(){
vc_map( array(
"name" => __( "Content box with Title", "mytheme"),
"base" => "titled_content_box",
"class" => "",
"category" => "Content",
"params" => array(
array(
"type" => "textfield",
"holder" => "div",
"class" => "",
"heading" => __( "Title", "mytheme"),
"param_name" => "title",
"value" => __("Box title", "mytheme"),
"description" => __("The title covering the content box", "mytheme")
),
array(
"type" => "textarea_html",
"holder" => "div",
"class" => "",
"heading" => __( "Description", "mytheme"),
"param_name" => "content",
"value" => '<p>Placeholder</p>',
"description" => __("The content", "mytheme")
)
)
));
}
// Setting values where necessary and fetching the template
function titled_content_box_func( $atts ){
extract( shortcode_atts( array(
'title' => 'title',
'content' => 'content'
), $atts) );
return include_vc_template('titled_content_box.php', $atts);
}
add_action ( 'vc_before_init', 'integrate_titled_content_box');
contents of the template used at the return statement:
<div class="titled-content-box">
<div class="title"><span><?php echo $atts['title']; ?></span></div>
<div class="content">
<?php echo $atts['content']; ?>
</div>
</div>
Does anyone know why my content-field is not loaded? The element itself is loaded, I can use it in VC... even the Title will be loaded and if I replace the field with a textbox, all still works fine and dandy...
My end-user wants to format his content and is not able to use html formatting.
The only function not included is the 'include_vc_template' function, but all that does is pretty much fetching a string-defined php-file on a predetermined location and injects the $atts array. In all other elements I've made that works perfectly fine.
However, for completeness i'll include it here;
function include_vc_template($template, $atts){
if(is_file(__DIR__.'/vc_templates/'.$template)){
ob_start();
include __DIR__.'/vc_templates/'.$template;
return ob_get_clean();
}
return false;
}
As this is a project i'm working on in my spare-time I can't help but to feel annoyed by a functionality not working as-documented... Most searches I've done simply referred my back to wpbakery's knowledge base page for vc_map()... Any pointers at all would be great!

Answer 1

Update you template callback function to:
function titled_content_box_func( $atts, $content ) {
$atts = shortcode_atts( array(
'title' => 'title',
), $atts) );
$atts['content'] = $content;
return include_vc_template('titled_content_box.php', $atts);
}
Update: 07-11-2016:
I would recommend using also vc_map_get_attributes function, which also combines all default values with your provided values.
As you can see in previous PHP function we used title attribute with default value title which is not compatible with the default value from vc_map (__("Box title", "mytheme")) and actually this is an error.
To avoid that errors please use vc_map_get_attributes function for $atts variable.
function titled_content_box_func( $atts, $content, $tag ) {
$atts = vc_map_get_attributes($tag, $atts);
$atts['content'] = $content;
return include_vc_template('titled_content_box.php', $atts);
}

Answer 2

The content is outputted but not a 100% correct, because it also mixes up the HMTL and creates extra paragraphs.
correct code is:
function titled_content_box_func( $atts, $content = null, $tag ) {
$atts = shortcode_atts( array(
'title' => 'title',
), $atts) );
$content = wpb_js_remove_wpautop($content, true); // fix unclosed/unwanted paragraph tags in $content
return include_vc_template('titled_content_box.php', $atts);
}