down-history: difference with bash/ksh

[cheusov]

This is a feature request.

On one of my systems I switched from bash to oksh as an interactive shell.
However, there are a number of annoying differences between bash/zsh and oksh.
One is a difference in how "down-history" command works.
On bash and zsh running "up-history" and then "down-history" commands bash/ksh switches to an empty line.
In oksh running "up-history" and then "down-history" commands remains previous history line for editing.
I hope idea is clear.

What do you think about implementing something like "down-history-or-empty" for compatibility with bash/ksh?