# How can I decrease Beamer's sidebar section distance?

When using Beamer with theme having sidebars and hiding inactive subsections, there is an unnecessary distance (looks like \baselineskip) between the already passed section and the next section. It looks like Beamer hides the subsection names, but not the vertical space used below the subsection names, and this wastes a lot of valuable space when I have several sections, say for a plenary talk. How can I omit that space? (I think the indentation separates enough the sections and subsections optically, so actually no need to make further separation, a normal line distance would be enough.)

\documentclass{beamer}
\usetheme[hideothersubsections] {Goettingen}
\usecolortheme{spruce}

\begin{document}

\section{Sec one}
\subsection{OneOne}
\begin{frame}{Frame Number 1}{Frame 1}
{1}
\end{frame}
\subsection{OneTwo}
\begin{frame}{Frame Number 2}{Frame 2}
{2}
\end{frame}
\section{Sec two}
\subsection{TwoOne}
\begin{frame}{Frame Number 3}{Frame 3}
{3}
\end{frame}
\end{document}


The default templates section in sidebar and section in sidebar shaded add a vertical space of 1ex. You can re-define those 2 templates to remove it.
\makeatletter