What's the use of `palette sidebar` in beamer's themes?

Question

I'm customising the appearance of my beamer slides, and am trying to set up a nice colour theme. I'm using the miniframes outer theme.

I have set up the four colours of the palette (primary, secondary etc), but I would like the miniframes outer theme to use another colour scheme, since the ones in the main palette are rather different. It would seem that the palette sidebar primary etc would be the recipe for that, but changing them does not have any effect. Indeed, looking at all the outer themes supplied with beamer, none of them seem to use the palette sidebar colours.

Is there actually any use of palette sidebar with the outer themes supplied with beamer, or will I have to write my own outer theme to use this palette?

Edit: Indeed, the palette sidebar colours do work with the sidebar outer theme, but not with the miniframes outer theme, as I would have hoped (as in the example below). I guess that means I do have to hack the miniframes outer theme to have a separate palette for the elements there.

\documentclass[]{beamer}

% \useoutertheme{sidebar}
\useoutertheme{miniframes}

% These colors only affect the sidebar outertheme
\setbeamercolor{palette sidebar primary}{fg=red}
\setbeamercolor{palette sidebar secondary}{fg=red}
\setbeamercolor{palette sidebar tertiary}{fg=red}

% These colors affect everything, including the miniframes outertheme
\setbeamercolor{palette primary}{fg=orange}
\setbeamercolor{palette secondary}{fg=green}
\setbeamercolor{palette tertiary}{fg=yellow}

% This is what I would like to have
\setbeamercolor{palette miniframes primary}{fg=magenta}
\setbeamercolor{palette miniframes secondary}{fg=magenta}
\setbeamercolor{palette miniframes tertiary}{fg=magenta}

\begin{document}

\section{AAA}
\subsection{BBB}
\begin{frame}
  \frametitle{A}  
\end{frame}
\begin{frame}
  \frametitle{B}  
\end{frame}

\end{document}

Answer 1

The palette sidebar xxx colours are used by most (all?) themes which have a sidebar. For example observe the colour of the subsection title in the following document:

\documentclass{beamer}

\usetheme{Berkeley}
\setbeamercolor{palette sidebar primary}{fg=red}

\begin{document}

\section{section name}
\subsection{subsection name}

\begin{frame}
    abc
\end{frame} 

\end{document}

---

If you want to change the colours in the headline of the miniframes theme, the easiest way is to set the section in head/foot colour.

\documentclass{beamer}

\useoutertheme{miniframes}

% These colors affect everything, including the miniframes outertheme
\setbeamercolor{palette primary}{fg=orange}
\setbeamercolor{palette secondary}{fg=green}
\setbeamercolor{palette tertiary}{fg=yellow}

% This is what I would like to have
\setbeamercolor{section in head/foot}{fg=magenta}
\setbeamercolor{subsection in head/foot}{fg=magenta}


\begin{document}

\section{AAA}
\subsection{BBB}
\begin{frame}
  \frametitle{A}  
\end{frame}
\begin{frame}
  \frametitle{B}  
\end{frame}

\end{document}