# Why is the indentation in my alltt environment not consistent?

I am writing a paper that involves some code. I set the code using alltt because I like to use \color and that doesn't seem to work in verbatim or listings. But I am having problems with indentation. Usually, it's exactly what is shown. But sometimes not. For instance:

\documentclass{article}
\usepackage{alltt}
\usepackage{color}
\usepackage{float}

\begin{document}
\begin{alltt}
proc template;
define statgraph fancybox;
begingraph;
entrytitle "Box plot w/histogram";
layout lattice/rows = 2 columns = 1
order = columnmajor rowweights = (.8 .2);
columnaxes;
columnaxis /griddisplay = on;
columnaxis /label = '' griddisplay = on;
endcolumnaxes;
boxplot x = ht y = wt;
barchart x =  ht y = wt;
endlayout;
endgraph;
end;
run;
\end{alltt}
\end{document}


the second row that starts with columnaxis is not indented to match the one just above.

I'm running pdflatex on a Windows machine.