@WebJoelJul 12.2007 — #I should know this, -but what do you mean by a "listbox"?
Some elements like "<object>" will have a default/grayed-out [I]vertical[/I] scrollbar, -even if the content does not need it. This is built into the shell of the browser and is intended to be an Accessibility thing so that a manner of 'viewing' is always indicated (even if not warranted).