deciding how windows split

[J. David Boyd]

I like my 'normal' behavior, where any command that creates a new window (like
'grep') opens the new window under where my current window is.

I recently got a new monitor, a very wide one, and I have my emacs stretched
out some.  Now new windows are opening to the right of the current one.

Is there some way to force emacs to continue to open new windows under my
current one.

I tried using customize-apropos on words that sounded like they might be what
I wanted, but can't find anything like that.

Thanks,

Dave