RE: how to open file window in Emacs

[Drew Adams]

> When I clicked the "Open File" in File menu, new window was not opened.
> Only I have to type the file name in the bottom command line.
> How to solve the issue?

That's the design.  In Emacs, `Open File' means create a buffer
with the name of an _existing_ file (not with no name).

Buffers in Emacs are named, and `Open File' creates a buffer
that visits an existing file, whose name you must provide.

Even `New File' requires that you first provide a file name.
It creates a buffer that is intended, by default, for saving
to a file.  (However, you _need not_ ever save it to a file.)

http://lists.gnu.org/archive/html/emacs-devel/2016-03/msg00629.html
http://lists.gnu.org/archive/html/emacs-devel/2005-10/msg00555.html