Typography customization for template

I have template NEWS2.
I am trying cutomize typography elements in file template/typography/ful.xml.

I want change block elements (div wrapped by paragraph)

from
<group name="Blocks" type="html">
<item name="block1"><![CDATA[<div class="gkblock-1">content here...</div>]]></item>
<item name="block2"><![CDATA[<div class="gkblock-2">content here...</div>]]></item>
<item name="block3"><![CDATA[<div class="gkblock-3">content here...</div>]]></item>
</group>

to
<group name="Blocks" type="html">
<item name="block1"><![CDATA[<p><div class="gkblock-1">content here...</div></p>]]></item>
<item name="block2"><![CDATA[<p><div class="gkblock-2">content here...</div></p>]]></item>
<item name="block3"><![CDATA[<p><div class="gkblock-3">content here...</div></p>]]></item>
</group>

When I put a modified element in the article editor TinyMCE to the article, paragraph is not inserted.

It is caused by the TinyMCE editor or properties Typography plugin?

Hi

It's being stripped by editor. A paragraph is not allowed to put a div inside, but it allows the other way around.