The graemlins are on a seperate "popup" browser window. JavaScript is used to open the window but as far as I can tell it's not DHTML related.
The newpost/preview/reply screens seem to all be under the same page... index.php. This may be the reason why the child window can still communicate with all of the screens.
I guess the only way for me to know this answer defninatively is to set something up and test it... lol