test.html

<div id="mainContainer">
    @Html.TXTextControl().TextControl(settings => {
        settings.Dock = DockStyle.Fill;
    }).Render()
</div>

<div class="row mb-3">
    <div class="col-12">
        <label for="container1" class="form-label">Document Editor 1</label>
        <div id="container1" class="editorContainer inactive">
            
        </div>
    </div>
</div>

<div class="row mb-3">
    <div class="col-12">
        <label for="container2" class="form-label">Document Editor 2</label>
        <div id="container2" class="editorContainer inactive">
           
        </div>
    </div>
</div>

<div class="row mb-3">
    <div class="col-12">
        <label for="container3" class="form-label">Document Editor 3</label>
        <div id="container3" class="editorContainer inactive">
        </div>
    </div>
</div>