Bug? WordPress 2.1 Firefox (popup window for parent of Page)

While managing a WordPress 2.1-site in Firefox, the popup window for setting the parent of a Page is running out of the Firefox-window. So, above a certain amount of Pages, when you need the vertical scrollbar for seeing the whole list of Pages, this scrollbar isn’t visible.
For just seeing and using the scrollbar of these pop up window you have to reduce the Firefox window.

Adrie Spruit