Struts JSP style="display:none" not working?

When I wanted to hide some 'div's from my JSP page, when I used

<div id="tab1" class="tabContent" style="display: none;">
This proves to be working on simple html version

<form name="ff".... >

But when I added struts form

<s: form action="StudentDetailsForm">
this makes the 'display:block' function freeze. This also happens to only some of the long forms.

To fix this what I did was set the struts form theme to simple and it worked!!!


<s:form action="StudentDetailsForm" theme="simple">