Subject: bug#2800: 23.0.91; Emacs has no response when
mini-buffer is too narrow to display information

> I opened two windows using C-x 3, and set the width of the right
> windows to a really small value (to be more precisely, it can display
> 50 characters per line). Then on the left line I run some command like
> M-x align<TAB>, as a result, the right window will be used as
> minibuffer and display auto-completion list. The bug is that, the list
> comes with all '\' on the right most and just cannot stop printing,
> and does not response to my control. In program 'top' I can see the
> CPU% of this emacs process is 100%.

I can't reproduce this. Does it happen with `emacs -Q'?