Custom Rich Text Editor is not working

Hi @artf, I've just created a custom plugin of the RTE using different libraries like CKEditor 5, TinyMCE 4 or pell but all of them with the same result that the editor is losing the focus so the buttons are not applying to the text content.

So on the image above if I press on Bold button then the effect is not applied to the content.

enable: function(el, rte){


            // If already exists just focus
            if (rte) {
                this.focus(el, rte); // implemented later
                return rte;
            }

            let rteToolbar = editor.RichTextEditor.getToolbarEl();
            [].forEach.call(rteToolbar.children, (child) => {
                child.style.display = 'none';
            });


            el.contentEditable = true;


            // Init Pell
            rte = window.pell.init({
                element: el,
                onChange: function (html) {
                    //console.log(html);
                }
            });

            el.focus();
            rte.focus();

            return rte;
        },

I think all my problem is on the enable function but I don't know why is happening this behaviour. Do you have any clue?

If I fix it then it will be really simple to include the 3 different plugins.