HyperlinkEvents are fired not just when the user clicks the link but also
when the mouse enters or exits the link area. Thus you'll want to check the type
of the event before changing the page with the getEventType()
method:
public HyperlinkEvent.EventType getEventType()
This will return one of the three mnemonic constants
HyperlinkEvent.EventType.EXITED
HyperlinkEvent.EventType.ENTERED
HyperlinkEvent.EventType.ACTIVATED