Dialog position

Dialog position

I have a page with a set of entries. Kind of like a list of forum posts. Each post has a link on it that opens a dialog box. However, the dialog always insists on forcing the page back to the top so the users loses their relative position on the page.  Why is the dialog forcing the page to scroll to the top? What do I need to specify to have it keep it's position relative to the entry in the list that it opened from?