diff --git a/docs/CREDITS b/docs/CREDITS
index 38a2eedc20..dc2ac19831 100644
--- a/docs/CREDITS
+++ b/docs/CREDITS
@@ -534,6 +534,7 @@ Jens Theeß
 Alexey Nemtsev
 Pascal Below
 Danny Attar
+Philipp Stephani
 
 The libmad team
 The wavpack team
diff --git a/manual/preamble.tex b/manual/preamble.tex
index 7969ca98c2..9398486168 100644
--- a/manual/preamble.tex
+++ b/manual/preamble.tex
@@ -79,7 +79,6 @@
 \usepackage{url}
 \urlstyle{sf}
 \usepackage{marvosym}
-\usepackage{ifthen}
 \usepackage{rotating}
 
 % pdf output: try pdf first, then png and jpg as file format
@@ -320,14 +319,13 @@
    commandchars=\\\{\}%
    }
 
-% Use the nopt command to exclude a certain defined feature from a sectio
+% Use the nopt command to exclude a certain defined feature from a section
 % Example:
 % \nopt{ondio}{This text will be excluded for ondios}
-\newcommand{\optnvalue}{0}
- \newcommand{\nopt}[2]{%
-   \renewcommand{\optnvalue}{0}\opt{#1}{\renewcommand{\optnvalue}{1}}%
-   \ifthenelse{\optnvalue > 0}{}{#2}%
- }
+\makeatletter
+\newcommand*\nopt[1]{\if\Opl@notlisted{#1}\expandafter\@firstofone
+   \else \expandafter\@gobble \fi}
+\makeatother
 
 % Use the reference to handle get a flexible reference command
 % usage \reference{ref_section}