Using "contenteditable" in Attachments

[meesix]

Hello,

I'm sorry, maybe it was discussed previously, but I couldn't find references. I want to create a specific element representing a two-column block. Here is what I'm doing;

blockTools.insertAdjacentHTML("afterbegin", " <button type="button" class="trix-button" data-trix-action="x-columns" title="Columns" tabindex="-1"><svg>...</svg</button>" )

const attachment = new Trix.Attachment({ content: "<div class='two-column' contenteditable></div>", contentType: "application/vnd.trix.columns.html" })

The div is added, but whenever I'm trying to put any content in it, the text immediately disappears.

I see in docs that Attachments can be moved or removed, but *not edited directly*, but maybe there is a simple tool for wrapping blocks of text into divs with classes?

[meesix]

As far as I understood, an alternative will be using custom blockAttributes, though it seems like it's still impossible to assign custom CSS classes to new blocks, isn't it?