Page code editor WYSIWYG removes bootstrap attributes (Prestashop 1.7)

[TheSmithsDoBusiness]

Hi everyone,

I'm trying to add a collapse panel on a page (Design > Pages on the left hand side). Specifically, I'm trying to add a Bootstrap collapse panel by inserting the code in the code viewer/editor ("<>") of the WYSIWYG editor as follows:

<div class="reference-container">
  <a href="#references" class="reference-button" data-toggle="collapse">References</a>
  <div id="references" class="collapse">collapse content</div>
</div>

When I click save, the 

data-toggle="collapse"

gets stripped/disappears/it's not saved. Why is this happening? I'm using the code editor to achieve the desired effect, so there should be no problem.

I've tried the same thing using the Prestablog module (using the exact same code inside the WYSIWYG code editor) and it worked perfectly. And the WYSIWYG editor seems to be the same for both pages and Prestablog blog posts...

Any ideas? I'm using Prestashop 1.7.6.5 btw.

Thanks

[TheSmithsDoBusiness]

I would really appreciate some help with this