\documentclass[a4paper]{article}

\usepackage{pgfplots}

\pgfplotsset{compat=1.5}

\usepackage{pgfplotstest_markers_and_clip}

\begin{document}

\TEST{
	clip mode=global,% we have mark layers 
	set layers,
	mark layer=axis foreground,
	title=blue mark above red line not clipped (mark layer),
}

\TEST{
	clip mode=global,% we have mark layers 
	set layers,
	mark layer=like plot,
	title={blue mark below red line clipped (mark layer=like plot)},
}
\end{document}

