Google Toolbar 2.0 doesn't let you get your work done with Outlook Web Access 5.5. While reading a mail item, the Reply, Reply To All and Forward buttons do not work. The popup-blocker appears to kill the new window.

To workaround, hold down the CTRL key while clicking the buttons. Continue to keep the CTRL key down until the new window displays, otherwise the popup-blocker will kick in if you let go of the CTRL key before the new window has come up.