Is it possible to get single-spaced marginnotes in a double-spaced document?
\documentclass[english,a4paper]{scrartcl}
\usepackage{babel}
\usepackage{blindtext}
\usepackage[draft]{fixme}
\linespread{2}
\begin{document}
\blindtext
\fxnote{this is a multi-line margin note note note note }
\blindtext
\end{document}
fixmepackage in the question title. Perhaps you could add a little example to show how you are getting your margin notes, and what method you are using to double space your document. – Seamus Jun 12 '12 at 12:52