I tried to define (my first! - I'm a LateX newbie) command to insert notes in the margins of my text, but it introduces gaps wherever I insert the command :-( The code for my command is:
\newcommand{\mnote}[1]
{
\mbox{}\marginnote{\color{red}\footnotesize#1}
}
And I use it for example like this:
\subsection{Differentiable Manifold}
\mnote{This is the central object in differential geometry.}A differentiable manifold is
but lo and behold, this has the unpleasant effect of adding white space before the letter of the paragraph:

How can I restore proper alignment for the initial letter of the paragraph?