Hi.
You can try 2 ways:
1) Set no-cache value for Cache-Control header in web.xml, like this:
<filter>
<filter-name>Header Filter</filter-name>
<filter-class>com.liferay.portal.kernel.servlet.PortalClassLoaderFilter</filter-class>
<init-param>
<param-name>filter-class</param-name>
<param-value>com.liferay.portal.servlet.filters.header.HeaderFilter</param-value>
</init-param>
<init-param>
<param-name>Cache-Control</param-name>
<param-value>No-cache</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>Header Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
2) Prevent Back button pressing with JS on each page, like this:
<script type="text/javascript">
function preventBack(){window.history.forward();}
setTimeout("preventBack()", 0);
window.onunload=function(){null};
</script>
First way is not good because it will disable caching and slow down your app.
Second way is not good because it will cause page "winking".
Maybe someone has better variants?
