[ESS] How to avoid split window when open a file?

[ronggui]

I install the  All-in-one installation file for MS Windows ( by
Vincent Goulet). When open a file by double-click, emacs split the
window automatically.
How can I avoid this? Thanks.

-- 
HUANG Ronggui, Wincent
PhD Candidate
Dept of Public and Social Administration
City University of Hong Kong
Home page: http://asrr.r-forge.r-project.org/rghuang.html