Hi, Does this problem persist after logging-out/logging-in and restarting? Sometimes the Dock becomes confused, and can cause transient problems with the Desktop. The Dock can be gracefully quit via the Activity Monitor (Applications > Utilities), and it will be automatically re-launched. If this does not work, perhaps both of you have corrupt Dock preferences? Maybe there is an app that causes this, and both of you have used that app?
James.
