Unwanted indent problem (1.2.1)

[Peter]

Hi,

I have a problem with an unwanted indent which I can't seem to get rid
of and I'd appreciate any help anyone could offer.

What I am trying to do is create a layout where I can have half-width,
centered paragraphs with the first line of the first such paragraph
*not* indented and then with subsequent paragraphs of the same style
having their first lines indented.

The problem I am having is that the first line of the first paragraph is
always indented by a small amount. I can get rid of it by editing the
LaTeX generated by LyX, but I'd naturally prefer not to do that.

I have attached three files. The LyX source, the LaTeX generated by LyX,
and the layout file which I am using for the document.

The change that I make to the LaTeX file to get rid of the indent is to
add a "%" at the end of the "\begin{authorsays}" line.

Any help greatly appreciated,

Peter

#LyX 1.2 created this file. For more info see http://www.lyx.org/
\lyxformat 220
\textclass test_book
\language english
\inputencoding auto
\fontscheme bookman
\graphics default
\paperfontsize default
\spacing single 
\papersize Default
\paperpackage a4
\use_geometry 0
\use_amsmath 0
\use_natbib 0
\use_numerical_citations 0
\paperorientation portrait
\secnumdepth 3
\tocdepth 3
\paragraph_separation indent
\defskip medskip
\quotes_language english
\quotes_times 2
\papercolumns 1
\papersides 1
\paperpagestyle default

\layout Standard

This is a test where I see where the margins are for what I am writing.
 This text in this paragraph will hopefully occupy three or more lines so
 I can see the full extent of the margins.
\layout AuthorSays

This is another test where I check to see how the characters in this new
 layout are presented on the screen to the readers.
\layout AuthorSays

It's possible, of course, that this layout is not particularly useful to
 anyone, but we will see if this is the case in the fullness of time.
\layout Standard

This is a test where I see where the margins are for what I am writing.
 This text in this paragraph will hopefully occupy three or more lines so
 I can see the full extent of the margins.
\the_end

delete_me.tex
Description: TeX document

#% Do not delete the line below; configure depends on this
#  \DeclareLaTeXClass[book]{Test book}

# Input general definitions
Input stdclass.inc

# Global parameters.
Sides           2
PageStyle       Headings

# There is no abstract environment in book.cls
NoStyle Abstract
        
# a few changes to the bibliography
Style Bibliography
  TopSep                4
  LabelString           Bibliography
  # label font definition
  LabelFont 
    Series              Bold
    Size                Huge
  EndFont
End

Style AuthorSays
  LatexType     Environment
  LatexName     authorsays
  NextNoIndent  1
  TopSep        0.5
  BottomSep     0.5
  Font
    Color       Blue
    Shape       Italic
  EndFont
  ParIndent     MM
  LeftMargin    MMMMM
  RightMargin   MMMMM
  Preamble
\newenvironment{authorsays}{%
\begin{center}%
\begin{minipage}{0.5\columnwidth}%
\setlength{\parindent}{2em}%
\itshape\noindent%
}{
\end{minipage}
\end{center}
}
  EndPreamble
End