MS Word TASK PANE?

How can I keep a doent from appearing in the task pane? Lets say I am planning a surprise party and I do not want anyone else finding out about it by seeing the announcement doent on a shared computer (no separate log in user id's). Lets ume users of the computer know how to access the task pane and like to work with it open. Is there a way to maintain the privacy of that work/doent?