outlook 2003, cursor disappears after 30seconds when editing message

When opening a received message, then click on edit message. You will see that the blue top bar highlights brighter which means you can edit text, then on every 10th and every 40st second in every minute it automatically “deselect” the blue top bar is no longer as bright and you must click on the mouse to continue editing text. This cant be right and users are asking me to fix it. How though??