Nested scope shift in nested tikzpictures?

Question

Please consider the following MWE:

\documentclass{book}

\usepackage[a4paper,twoside,hmargin=3cm]{geometry}

\usepackage{tikz,tikzpagenodes}
\usetikzlibrary{calc,positioning}

\newif\ifoutertikznest
\outertikznesttrue
% \outertikznestfalse


\begin{document}

\begin{tikzpicture}[overlay,remember picture,anchor=north west,inner sep=0pt, outer sep=0pt,line width=2pt]


  \node[draw=red,minimum size=2cm,anchor=north west,inner sep=0pt,outer sep=0pt] at (0,0) (A1) {%
  \ifoutertikznest %
    \begin{tikzpicture}[overlay,remember picture,anchor=north west,inner sep=0pt, outer sep=0pt,line width=2pt] % ***
  \else
    }; % ***
  \fi


  \node[draw=blue,minimum size=2cm,anchor=center,inner sep=0pt,outer sep=0pt] at (current page.center) (A2) {};

  \node[draw=green,minimum size=2cm,anchor=north west,inner sep=0pt,outer sep=0pt] at (current page.north west) (A3) {};


  \begin{scope}[shift={(0.5,1.0)}] %
    \node[draw=magenta,minimum size=2cm,anchor=north west,inner sep=0pt,outer sep=0pt] at (0,0) (A4) {};
    \begin{scope}[shift={(0.5,1.0)}] %
      \node[draw=yellow,minimum size=2cm,anchor=north west,inner sep=0pt,outer sep=0pt] at (0,0) (A5) {};
    \end{scope}
  \end{scope}


  \ifoutertikznest %
  \end{tikzpicture} % ***
  }; % ***
  \fi

\end{tikzpicture}


\end{document}

If you enable the \outertikznestfalse line, then there is no additional wrapping in a tikzpicture, and the nested scope shifts look as expected (image left):

However, if the rest of the image is "wrapped" under the first node (which requires an extra tikzpicture) - and this is the state, if outertikznesttrue line is enabled instead - then something is not quite right with the relative shift of the nested scopes (image right).

While I did expect the extra tikzpicture to influence the absolute placement in some way - I didn't expect that it would disturb the relative shifts between the scopes. Is this expected behavior? And how could I have the same relative position of the nested scopes (as on image left), even if I have an extra tikzpicture wrapper?

Answer 1

The result is normal. You can add \fill (0,0) circle (2pt);

  \fill (0,0) circle (2pt);
  \begin{scope}[shift={(0.5,1.0)}] %
    \node[draw=magenta,minimum size=2cm,anchor=north west,inner sep=0pt,outer sep=0pt] at (0,0) (A4) {};
    \begin{scope}[shift={(0.5,1.0)}] %
      \node[draw=yellow,minimum size=2cm,anchor=north west,inner sep=0pt,outer sep=0pt]  at (0,0) (A5) {};
    \end{scope}
  \end{scope}

You can see that you change the origin point with the nested tikzpicture. In this case the orign point in the center of the red node, in the other case it's the north west point (normal with your code).