I am trying to understand the reason behind doing this.
<fieldset id="fieldset-1015" class="x-fieldset x-fieldset-with-title x-fieldset-with-header x-fieldset-default" style="border-width:0;">
<legend id="fieldset-1015-legend" class="x-fieldset-header x-fieldset-header-default">
<div id="fieldset-1015-body" class="x-fieldset-body ">
<span id="fieldset-1015-outerCt" style="display: table; width: 100%; table-layout: fixed;">
<div id="fieldset-1015-innerCt" class="" style="display:table-cell;height:100%;vertical-align:top;">
</div>
</span>
</div>
</fieldset>
I know this a very debatable question. But I want to understand why ExtJS chose to do it this way for their layouts.
I don't see divs inside span in other layout like layout=container
Block elements inside inline elements is discussed in these questions(and many more) -