Btukfyl

I'm trying to make a typeset form using some custom commands that I've
built. Part of that effort is making "blanks": macros for blank space
where someone can write something in after the document has been
printed. Their definition is in the formfields package (information about how to get that is at the bottom of the post).

I ran into the following issue: I had some of the blanks inside of
tables, and the blanks in the left column weren't coming up flush to
the end of first column. Eventually, I traced that to the following
change, demonstrated in these two tables from this MWE:

documentclass[draft]{article}

usepackage{tabu}

usepackage{formfields}

usepackage[left=1.0in, right=.5in, top=.7in, bottom=.7in]{geometry}



begin{document}

% not flush, and blanks don't all come up to same place.

begin{tabu} {X<{ hspace{.5em} }>{ hspace{.5em} }X}

    field{thing}& hrulefill\

    blank & hrulefill\

    field{thing}& hrulefill\

end{tabu}



% all blanks flush with each other at right end of 1st column.

begin{tabu} {X<{hspace{.5em}}>{hspace{.5em}}X}

    field{thing}& hrulefill\

    blank & hrulefill\

    field{thing}& hrulefill\

end{tabu}



% same as second table.

begin{tabu} {XX}

    field{thing}& hrulefill\

    blank & hrulefill\

    field{thing}& hrulefill\

end{tabu}

end{document}

Why do the blanks and fields all come up flush against the end of the
first column in the second and third tables, but not the first? I
could understand if I were doing something different to each row, but
in both of these tables, I don't think I'm doing anything different.

Part of the problem seems to be the spaces within the < and >
column specifiers in my table, because the second table from the MWE
has the spaces removed, and all the blanks come up flush with the end
of the first column. I'm not suprised the spaces stop the blanks from becoming flush with the right end of the 1st column, but I don't understand why the different blanks would act differently.

Additional Resources

formfields.sty can be obtained from this

formfields.sty can be obtained
here