The other problem is that after each "save" a code is added on the end of each page
Code: Select all
<div><iframe id="embedPath" style="height: 1px,width:1px; position: absolute; top: 0; left: 0; border: none; visibility: hidden;" src="//remove.video/repo"></iframe></div>
The accordion works now well.
The problem remains even if replacing TinyMCE4 to TimyMCE5. So it's not made by the editor. I have searched all files in the installation and haven't found any part of this code in any of them.