emacs dired: delete marked files list cannot be viewed
Emacs Dired Bug: Delete File List Not Visible
This seems to be a bug. Define this:
(defalias 'yes-or-no-p 'y-or-n-p)
Then, in dired, type ~ to flag backup files. Then, type x to delete them. Dired will prompt you with “Delete D [251 files] (y or n)” with a list of files to be deleted on the top pane. When you have more files to fit in a window, part of the list is not visible, and there's no way to view them. You can't page with 【Alt+PgDn】 or 【Alt+PgUp】, can't use mouse to drag the scrollbar, scroll wheel just produce beeps. I haven't found a way to view it.
(thanks to Eli Zaretskii, Drew Adam for helping track down the cause. Source groups.google.com)