When performing administrative tasks in Project Web Access and get interrupted, session can timeout causing the loss of changes being worked on, such as making changes to a view.
Increase the session timeout value by following these directions:
1. Go to SharePoint Central Admin
2. Go to Application Manager
3. Select Configure Session State
4. Under Timeout, change the default value stored there
Note: A long session time out makes the system more susceptible to attacks from scripts running on other pages that may have loaded in your browser.