There are no limitations on the level amount. Only one thing must be mentioned, be sure to set the 'fit' property to true for your sub tabs.
I do have the fit property set. I am missing something. see HTML below. Just the sub tab section.
Thank you for your attention
<div title="Sub Tabs" data-options="fit:true,plain:true" style="padding:10px;">
<div class="easyui-tabs" data-options="fit:true,plain:true">
<div title="Title1" style="padding:10px;">efore you continue please account for your VFC Returns <a href="#">HERE.</a></strong></span></div>
<div title="Title2" style="padding:10px;">Jump 2</a></div>
<div title="Title3">
<div title="Sub Tabs 02" data-options="fit:true,plain:true" style="padding:10px;">
<div class="easyui-tabs" data-options="fit:true,plain:true">
<div title="Title7" style="padding:10px;">Content 4</div>
<div title="Title8" style="padding:10px;">Content 5</div>
<div title="Title9" style="padding:10px;">Content 6</div>
</div>
</div>
</div>
<div title="Title4" style="padding:10px;">Content 4</div>
<div title="Title5" style="padding:10px;">Content 5</div>
<div title="Title6" style="padding:10px;">Content 6</div>
</div>
</div>