A common request for previous versions of Project Server was the ability to extend the security timeout of pages within the tool. Why this was requested was users typically started an action, got called away, or popped out for a coffee, then came back to the page they were editing, pressed save only to be told that the page had timed out and all their edits had been lost. Now this was not across the whole of tool, but only certain pages like editing views, SharePoint team sites etc.
Whilst there are numerous posts outlining how to set this in 2007, with the move to the 2010 platform, the setting has moved to deep within Central Administration. To find it, navigate to Central Administration and choose Manage Web Applications.
Select the web application that hosts your PWA instance and highlight it. Then click on the General Settings button on the toolbar.
A dialog will be displayed outlining the settings for that web application, scroll down about half way until you see ‘Web Page Security Validation. You will see the default time is set at 30 minutes.
Simply update that setting and your web application will now respect that time out setting. A word of warning however, the setting will affect all sites hosted in that web application, so if you portal and PWA instance are on the same web app, they are both going to have the increased timeout.