Neither can I. My drop-down list shows only 15 choices, with no scroll available, and I can’t use the down arrow to go further (and I have have more than 14 published pages (15th choice is “no parent”) to choose from).
I use unpublished pages as parents (shown in bold) to create this effect: blog.com/pix/2008/page, and blog.com/pix/2009/page.
Currently, it won’t work this way when I update existing pages or publish new ones. Manually editing the stub/permalink won’t work because the slash is automatically removed.