What I have is

if (react.isValidElement(content)){
    content = React.cloneElement(content,{
        className: joinClasses(content.props.className, contentClass),
    });
} else{
    content = React.createElement(
        'div',
        {
            className:contentClass,
            'tabIndex': 0,
        },
        content
    );
}

In the elements that were created with createElement, the tabIndex is working and we can see the taboutline. However, with the cloneElement, theres no taboutline and we can't tab to it.