\documentclass[a4paper,landscape,KOMA,display]{powersem} % landscape, no panel

% some of the following combinations also lead to strange results:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%\documentclass[a4paper,landscape,KOMA]{powersem} % landscape, and a proper panel
%\documentclass[a4paper,landscape]{powersem} % landscape, but not centered, no panel
%\documentclass[landscape,display]{powersem} % NOT landscape (?) and a half panel
%\documentclass[KOMA,display]{powersem} % landscape (!?) but no panel
%\documentclass[display]{powersem} % not landscape but a (half) panel
\usepackage[cnavo]{ifmslide}

%% has to be after \usepackage{ifmslide} and before \begin{document}
\pagestyle{empty}

\begin{document}

%% the \panelposition command has to be inside the document
%% environment -- why?
\panelposition{outsidebottom}
\begin{slide}
  \begin{center}
    Hi!
  \end{center}
\end{slide}
\end{document}