Multiple instances of TinyMCE are removing <p> tag

Question

I'm using the following code in functions.php to add a TinyMCE box on custom field textareas inside the Editor:

add_action('admin_print_footer_scripts','FT_TinymceCustom',99);
function FT_TinymceCustom()
{
?>
<script type="text/javascript">
    jQuery(function($)
    {
        var i=1;
        $('.customEditor textarea').each(function(e)
        {
            var id = $(this).attr('id');

            if (!id)
            {
                id = 'customEditor-' + i++;
                $(this).attr('id',id);
            }

            tinyMCE.execCommand('mceAddEditor', false, id);
        });
    });
</script>
<?php

}

However, on any box I add this to, it seems to cause a bug that deletes paragraph tags.

So if I enter this in the custom TinyMCE textarea (source view):

<p>test</p>p>test</p>

After saving, this is what shows in the box:

p>test test</p>

This only occured after the latest 3.9 update, which forced me to modify my JS code above to make it work.

Answer 1

Since that SO link is to my question, I will re-post it and expand on it here.

TinyMCE does NOT save "p" tags in the editor, instead linebreaks and the like are converted into p tags by WordPress functions (such as wpautop(). So the solution was a combination of altering my textbox to look like:

<textarea class="wysiwyg" rows="10" cols="50" name="some_textarea" rows="3"><?php echo wp_richedit_pre($value); ?></textarea>

Then on the frontend to re-apply all the default filters that are added to the_content.

// in functions.php
add_filter( 'meta_content', 'wptexturize'        );
add_filter( 'meta_content', 'convert_smilies'    );
add_filter( 'meta_content', 'convert_chars'      );
add_filter( 'meta_content', 'wpautop'            );
add_filter( 'meta_content', 'shortcode_unautop'  );
add_filter( 'meta_content', 'prepend_attachment' );
add_filter( 'meta_content', 'do_shortcode');

and then where you need to print the info:

echo apply_filters( 'meta_content', $data );

You could apply the content filters directly, but I find that a lot of plugins add content to that as well and I ended up with social sharing buttons everywhere and so came up with this solution.

You can check my github for repeatable, sortable, tinyMCE-enabled text editors (using WP Alchemy, but I think the JS could be adapted for use without WPA)

Answer 2

Found the answer here: https://stackoverflow.com/questions/5956174/tinymce-editors-in-meta-boxes-not-saving-p-tag

You must run wpautop() on the output of the tinymce.