Wrong list indentions with trumbowyg

I tried to use trumbowyg in my code but when I click on the “indent” button within the selected texts are an ordinal list. It directly puts the ul tag in the parent ul instead of putting it in il tag before.

For example:

<ul>
    <ul>
        <li><u>EDVA activities: </u></li>
        <ul>
            <li>&nbsp;3 flights this week:  1 gold flight.</li
        </ul>
        <li>&nbsp;8 shuttles</li>
    </ul>
</ul>
   

Instead of:

<ul>
    <li>
        <ul>
            <li><u>EDVA activities: </u></li>
            <li>
                <ul>
                    <li>&nbsp;3 flights this week:  1 gold flight.</li>
                </ul>
            </li>
            <li>&nbsp;8 shuttles</li>
        </ul>
    </li>
</ul>

How can I solve this problem?