# Arrow in sequence diagram is too short for text

I'm struggling with pgf-umlsd. As you can see in the image the arrow does not "grow" with my text length, producing a very ugly layout:

My code:

\documentclass[a4paper]{article}

\usepackage{mathtools}
\usepackage{tikz}
\usepackage[underline=false,rounded corners=false]{pgf-umlsd}

\begin{document}

\begin{sequencediagram}
\newinst{s}{Server}{}

\begin{call}{t}{Anfrage}{s}{Parameter $P=e(K,K_{pub})$}
\end{call}

\end{sequencediagram}
\end{document}


I tried using a box with \begin{call}{t}{Anfrage}{s}{\makebox[10em]{Parameter $P=e(K,K_{pub})$}} but this doesn't change the result, no matter if I put it to the top or bottom arrow. Is there a possibility to fix this?

-

You can move the \newinst with an optional argument: \newinst[3]{s}{Server} (see the documentation, example 1.1.4; unfortunately, the documentation is not very "talkative" and does explain almost exclusively by example; the source pgf-umlsd.sty might be helpful: all commands are listed with a full usage example).

\documentclass[a4paper]{article}
\usepackage{mathtools}
\usepackage{tikz}
\usepackage[underline=false,rounded corners=false]{pgf-umlsd}

\begin{document}

\begin{sequencediagram}
\begin{call}{t}{Anfrage}{s}{Parameter $P=e(K,K_{pub})$}