Shibboleth's default logout behavior should prevent you from losing work if you log out of one service with information still in progress in another. Here's how it works.
One of Shibboleth's major benefits for campus users is in reducing the number of times you have to enter your NetID and password. Signing in to Shibboleth means that you can be recognized by all of the services that accept its single sign-on credentials for you.
However, an equivalent single sign-off has the potential to create unintended consequences: If you log out of one system and that one logout disconnected all your Shibboleth sessions, you could lose unsaved work in other browser tabs.
In order to prevent that from happening, the campus standard behavior is to provide single sign-in and multiple sign-out. Logging out in one tab doesn't automatically close you out of the others, although in some cases you may be prompted for another login.
If you've signed up for both Google Apps at Illinois and Box, you can see how it works as follows:
Sometimes you want to log out of all your sessions at the same time, especially if you've been using a computer lab or another person's computer.
If your browser isn't set to remember your sessions across browser restarts, then closing the web browser (all tabs and all windows) will log you out of all your sessions.
However, if your browser is set to remember your sessions across restarts, then you'll need to log out of each Shibboleth-authorized window separately.