resize-minibuffer-mode has no effect in some cases

Greetings, With XEmacs 21.2-b43 and xemacs-sumo-2001-02-04.tar.gz as the SUMO package, xemacs -q, M-x resize-minibuffer-mode RET, an attempt to go very deep in a directory hierarchy, enter some empty directory, go back to its parent and delete that empty directory, results to a question whether the corresponding buffer should also be deleted. Since one was very deep in the directory hierarchy, the prompt will be so long that it doesn't fit to one line. Unfortunately, only one line is shown, despite the fact that resize-minibuffer-mode was enabled. A screenshot at <URL:http://www.iki.fi/azure/var/bugreports/xemacs-minibuffer.png> illustrates the situation (XEmacs wasn't started with -q in this case, but I verified the problem occurs also when started with -q). -- Hannu