Wie kann ich unerwünschten Abstand im tableofcontents in beamer beseitigen?

\documentclass{beamer}
\usetheme{AnnArbor}

\makeatletter

\def\beamer@sectionintoc#1#2#3#4#5{%
  \ifnum\c@tocdepth>0%
  \ifnum#4=\beamer@showpartnumber%
  {
  \beamer@saveanother%
  \gdef\beamer@todo{}%
  \beamer@slideinframe=#1\relax%
  \expandafter\only\beamer@tocsections{\gdef\beamer@todo{%
      \beamer@tempcount=#5\relax%
      \advance\beamer@tempcount by\beamer@sectionadjust%
      \ifnum\beamer@tempcount>0
        \edef\inserttocsectionnumber{\the\beamer@tempcount}%
      \else
        \def\inserttocsectionnumber{}%
      \fi%
      \def\inserttocsection{\hyperlink{Navigation#3}{#2}}%
      \beamer@tocifnothide{\ifnum\c@section=#1\beamer@toc@cs\else\beamer@toc@os\fi}%
      {
        \ifbeamer@pausesections\pause\fi%
        \usebeamertemplate{toc section itemsep}%
        {%
          \hbox{\vbox{%
              \def\beamer@breakhere{\\}%
              \beamer@tocact{\ifnum\c@section=#1\beamer@toc@cs\else\beamer@toc@os\fi}{section in toc}}}%
         \par%
        }%
      }%
    }
  }%
  \beamer@restoreanother%
  }
  \beamer@todo%
  \fi\fi%
}

\long\def\beamer@subsectionintoc#1#2#3#4#5#6{%
  \ifnum\c@tocdepth>1%
  \ifnum#5=\beamer@showpartnumber%
  {%
    \beamer@saveanother%
    \gdef\beamer@todo{}%
    \beamer@slideinframe=#1\relax%
    \expandafter\only\beamer@tocsections{\gdef\beamer@todo{%
      \ifbeamer@pausesubsections\pause\fi%
      \beamer@tempcount=#6%
      \advance\beamer@tempcount by\beamer@sectionadjust%
      \edef\inserttocsectionnumber{\the\beamer@tempcount}%
      \def\inserttocsubsectionnumber{#2}%
      \def\inserttocsubsection{\hyperlink{Navigation#4}{#3}}%
      \beamer@tocifnothide{\ifnum\c@section=#1\beamer@toc@css\else\beamer@toc@oss\fi}%
      {%
        \usebeamertemplate{toc subsection itemsep}%
        \def\beamer@breakhere{\\}%
        \beamer@tocact{\ifnum\c@section=#1\ifnum\c@subsection=#2\beamer@toc@css\else\beamer@toc@oss\fi\else\beamer@toc@ooss\fi}
        {subsection in toc}%
      }%
    }}%
    \beamer@restoreanother%
  }
  \beamer@todo%
  \fi\fi%
}

\long\def\beamer@subsubsectionintoc#1#2#3#4#5#6#7{%
  \ifnum\c@tocdepth>2%
  \ifnum#6=\beamer@showpartnumber%
  {
    \beamer@saveanother%
    \gdef\beamer@todo{}%
    \beamer@slideinframe=#1\relax%
    \expandafter\only\beamer@tocsections{\gdef\beamer@todo{%
      \ifbeamer@pausesubsections\pause\fi%
      \beamer@tempcount=#7%
      \advance\beamer@tempcount by\beamer@sectionadjust%
      \edef\inserttocsectionnumber{\the\beamer@tempcount}%
      \def\inserttocsubsectionnumber{#2}%
      \def\inserttocsubsubsectionnumber{#3}%
      \def\inserttocsubsubsection{\hyperlink{Navigation#5}{#4}}%
      \beamer@tocifnothide{\ifnum\c@section=#1\beamer@toc@csss\else\beamer@toc@osss\fi}%
      {%
        % <<<<<
        \beamer@tocact{\ifnum\c@section=#1\ifnum\c@subsection=#2\ifnum\c@subsubsection=#3\beamer@toc@csss\else\beamer@toc@osss\fi\else\beamer@toc@oosss\fi\else\beamer@toc@ooosss\fi}
        {toc subsubsection itemsep}%
        % =====
        %\usebeamertemplate{toc subsubsection itemsep}
        % >>>>>
        \def\beamer@breakhere{\\}%
        \beamer@tocact{\ifnum\c@section=#1\ifnum\c@subsection=#2\ifnum\c@subsubsection=#3\beamer@toc@csss\else\beamer@toc@osss\fi\else\beamer@toc@oosss\fi\else\beamer@toc@ooosss\fi}
        {subsubsection in toc}%
      }%
    }}%
    \beamer@restoreanother%
  }
  \beamer@todo%
  \fi\fi%
}

\makeatother

\setbeamertemplate{toc section itemsep}{\vskip1.5\baselineskip}
\setbeamertemplate{toc subsection itemsep}{\vskip1\baselineskip}
\setbeamertemplate{toc subsubsection itemsep}{\vskip0.5\baselineskip}

\begin{document}
\begin{frame}
\tableofcontents[hideallsubsections]
\end{frame}
\section{A}
\begin{frame}
\tableofcontents[hideothersubsections,sectionstyle=hide]
\end{frame}
\subsection{A1}
\begin{frame}
\tableofcontents[subsectionstyle=show/shaded/hide,sectionstyle=hide]
\end{frame}
\subsubsection{A1a}
\begin{frame}
\end{frame}
\subsubsection{A1b}
\begin{frame}
\end{frame}
\subsection{A2}
\begin{frame}
\end{frame}
\subsection{A3}
\begin{frame}
\end{frame}
\section{B}
\begin{frame}
\end{frame}
\end{document}