Using "xfce4-terminal 0.6.3 (Xfce 4.10)", I did

   emacs-24.3.91 -Q -nw
   M-x menu-bar-open RET

then simply held down the down array, and very quickly got it to look
like the first attached image. By holding down the down arrow for a bit,
then the up arrow for a bit, then the down arrow, etc, I got the second
image. It's not 100% reproducible, but seemed to happen fairly often.
I don't expect to hold down the arrow keys in normal usage. :)