In the following MWE I'd like the second framebox to look the same as the first one (see the image below).
\documentclass[10pt]{article}
\begin{document}
\setlength{\fboxsep}{0pt}
\setlength{\fboxrule}{.1pt}
\framebox[\width]{A frame.}\par
\framebox[\width]{
\begin{minipage}{4em}
A frame.
\end{minipage}}
\end{document}
Any clue ?
Thanks in advance.

h]{Either don't add that space (line break) or put a%there to hide it. – David Carlisle Jan 08 '16 at 10:53minipagetry editing your\framebox[\width]{A frame.}to have a space or newline before theA– David Carlisle Jan 08 '16 at 10:54