I want to draw on a tikz-spy and the new line should be covering the ones copied by the spy. E.g.:
\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{spy,shapes}
\pgfdeclarelayer{bg} % declare background layer
\pgfsetlayers{bg,main} % set the order of the layers (main is the standard layer)
\begin{document}
\begin{tikzpicture}[spy using outlines={rectangle, width=4.5cm, height=3cm, magnification=4, connect spies,every spy on node/.append style={thin}},hide/.style={opacity=1}]
\begin{scope}
\draw circle (8) node[yshift=8.8cm,align=center] {};
\draw circle (8.2) node {};
\draw (-5,7.4) -- (5,7.4);
\end{scope}
%\begin{pgfonlayer}{bg} % select the background layer
\spy [black] on (-3.4,7.4) in node (spyleft) [left] at (-0.5,4.5);
%\end{pgfonlayer}
%\begin{pgfonlayer}{main} % select the main layer
\draw[line width=2pt,color=blue] (-3.3,4.5) -- (-1.35,4.5) -- (-1.35,5.35) -- cycle;
%\end{pgfonlayer}
\end{tikzpicture}
\end{document}
should have the blue triangle on top of the black lines. Explicitly putting the parts of the drawing in a layer doesn't seem to help. Is there a specific spy-layer that I could address?
(Ideally I'd also like the corners of the triangle to be defined by the intersections of circles and the line but for now I'm happy to position it by hand if only I could get the layers right...)