Vikas,
If I remember correctly, the GWT Hyperlink does not appear as a <a> in
the generated HTML. Instead, it is a <div> with a javascript event
handler attached to it. I believe that overwriting the HTML (using
DOM.setInnerHTML and possibly Hyperlink.setHTML) detaches the
javascript event handler. And as mentioned by other posters, this is
probably not what you want. The Hyperlink creates history tokens and
only goes to internal states of the app. This behavior is misleading,
and we stopped using the widget altogether. We wrote
our own SimpleHyperlink class that uses an <a> HTML tag as one would
expect a hyperlink to do, and it behaves wonderfully in all browsers.
Hope that helps,
David