No, and in 6 years of that interface, no one else has asked.  (The 
information on open windows is not even retained.)
You might like to try the single-window pager option in the preferences.
On Wed, 27 Apr 2005, Ronnen Levinson wrote:
> I often wind up with many help windows cluttering my RGui screen when
> running Windows R 2.0.1. Is there an R instruction to close one or more
> help windows, or an RGui command to close all help windows?
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595