Missing screen tips

Hello all.I am learning Word2003. In my book it says "hold the mouse over the right margin boundry on the horizontal ruler where the margin is located.The mouse pointer changes to a double-sided arrow when you hold it over the margin,and a screen tip appears that says"Right Margin".My mouse pointer does not change to a double-sided arrow and no screen tip apears that says "Right Margin".(I have screen tips turned on.Please somebody please help me please.Thank you.Linda