Strange line break in tablenotes (of ThreePartTable)

Question

I'm using the threeparttable and tablenotes packages to create footnotes for tables. I've found that to get the design I want (hanging symbols, not superscript), I can simply use the para option and manually punch in my footnotes, rather than use the conventional \item[] syntax. However, doing it this way produces some strange space between the symbol and text (even if I wrap it in braces, or use a very short line of text). Putting an mbox around the note solves the problem, but the text runs out of the table width. Putting a pbox around it doesn't solve the problem either.

I'm curious as to why this is happening, and what simple solution there may be. Please see the image and code below for an explanation.

MWE

\documentclass{scrartcl}

\usepackage{booktabs}
\usepackage[para]{threeparttable}
\usepackage{tablefootnote}
\renewcommand{\TPTnoteSettings}{\footnotesize}
\newcommand{\tabfnote}[2]{\llap{#1. }#2}

\begin{document}
\begin{table}[tbph]
    \begin{threeparttable}[t]
        \begin{tabular}{ll} \toprule
            Alpha & Beta \\
            Gamma & Delta \\ \bottomrule
        \end{tabular}
        \begin{tablenotes}
            \tabfnote{a}{Why is there space above?}\\
            \tabfnote{b}{But not above this one...}\\
            \tabfnote{c}{Or this one}
        \end{tablenotes}
    \end{threeparttable}
\end{table}
\end{document}

Answer 1

Something happens with vertical mode at the very beginning of tablenotes, which I do not really understand, but adding a \leavevmode at the beginning of the definition of \tabfnote solves the problem:

\documentclass{scrartcl}

\usepackage{booktabs}
\usepackage[para]{threeparttable}
\usepackage{tablefootnote}
\renewcommand{\TPTnoteSettings}{\footnotesize}
\newcommand{\tabfnote}[2]{\leavevmode\llap{#1. }#2}

\begin{document}

\begin{table}[tbph]
    \begin{threeparttable}[t]
        \begin{tabular}{ll} \toprule
            Alpha & Beta \\
            Gamma & Delta \\ \bottomrule
        \end{tabular}
        \begin{tablenotes}
            \tabfnote{a}{Why is there space above?}\\
            \tabfnote{b}{But not above this one...}\\
            \tabfnote{c}{Or this one}
        \end{tablenotes}
    \end{threeparttable}
\end{table}

\end{document}