> Sorry, actually you are right, let's add a new option.
> Will do this soon.

The reason why a new option is needed is because display-warning
doesn't move point to the bottom line with the last message.

So when the warning buffer will be displayed at the bottom of
the screen in a narrow window, but the window always stays
displaying the top of the warning buffer, the users will miss
the last unseen message.

To solve this problem, a new option 'warning-display-at-bottom'
(whose name has the same prefix as all other options in the same file)
will scroll the bottom window, so the last message will always
be visible to the user.