Clear CSS Tool Tip in Opera

I am using the following code to create a Tool Tip when I mouse over a link.
It works fine in IE and Fx, however, in Opera the tip doesn't disappear when I move the mouse away from the text.
Is this a problem with Opera or is it my code?

Code:

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<STYLE TYPE="text/css">
  a.info{
    position:relative; /*this is the key*/
    z-index:24; background-color:#FFFFFF;
    color:#000;
    cursor: help;
    text-decoration:none
  }
  a.info:hover{
    z-index:25;
    background-color:#89B3E0;
    text-decoration:none
  }
 
  a.info span{display: none}

  a.info:hover span{ /*the span will display just on :hover state*/
      display:block;
      position:absolute;
      top:2em; left:2em; width:15em;
      border:2px solid black;
      padding: 2px;
      background-color:#89B3E0; color:#000;
      text-align: center;
      text-decoration:none
  }
  </STYLE>

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