Hi jvance,
How are you applying the filter? Are you using a custom screen or standard screen? If you are using the standard calendar when you apply the filters do the usernames display along the top? What is the exact tab link name for the screen you are using?
-Michael
Michael Melo
Product Manager
Method Integration Inc.
Website: http://www.method.me
LinkedIn: http://www.linkedin.com/in/MichaelMelo