\setbeamertemplate{headline}
{%
    \placetarget
    \let\placetarget\relax
    \begin{beamercolorbox}[colsep=1.5pt]{upper separation line head}%
    \end{beamercolorbox}
    \begin{beamercolorbox}{section in head/foot}
        \vskip2pt
        \usebeamerfont{section in head/foot}\usebeamercolor[fg]{section in head/foot}%
        \color{fg!80!bg}
        % \adjustbox{
        %     set depth=2pt,
        %     padding={5pt 5pt 5pt 5pt},
        %     bgcolor=bg!80!orange,
        %     rndframe={color=red!20!orange}{0pt 3pt 0pt 3pt},
        %     margin={0pt 0pt 10pt 0pt}
        % }{%
        %     \hyperlink{oefeningen1}{\customhead{5}{Oefeningen}}%
        % }%
        \adjustbox{
            set depth=2pt,
            padding={5pt 5pt 5pt 5pt},
            rndframe={color=navigationTileOutline,width=1pt}{3pt 0pt 3pt 0pt},margin={10pt 0pt 0pt 0pt}
        }{%
            \hyperlink{textdocument}{\customhead{2}{Text document}}%
        }%
        \adjustbox{
            set depth=2pt,
            padding={5pt 5pt 5pt 5pt},
            %bgcolor=bg!80!orange,
            %bgcolor=structure.bg!80!orange,
            bgcolor=exerciseTileBackground,
            rndframe={color=exerciseTileOutline,width=1pt}{0pt 3pt 0pt 3pt},
            margin={-1pt 0pt 10pt 0pt}
        }{%
            \hyperlink{exercises1}{\customhead{3}{Exercises}}%
        }%
        \adjustbox{
            set depth=2pt,
            padding={5pt 5pt 5pt 5pt},
            rndframe={color=navigationTileOutline,width=1pt}{3pt 0pt 3pt 0pt},margin={10pt 0pt 0pt 0pt}
            % rndcorners={3pt 0pt 3pt 0pt}
        }{%
            \hyperlink{formulas}{\customhead{4}{Formulas}}%
            \hspace{5pt}$ \cdot $\hspace{5pt}%
            \hyperlink{figures}{\customhead{5}{Figures}}%
            % \hspace{5pt}$ \cdot $\hspace{5pt}%
            % \hyperlink{tabellen}{\customhead{8}{Tabellen}}%
        }%
        \adjustbox{
            set depth=2pt,    
            padding={5pt 5pt 5pt 5pt},
            bgcolor=exerciseTileBackground,
            rndframe={color=exerciseTileOutline,width=1pt}{0pt 3pt 0pt 3pt},
            margin={-1pt 0pt 10pt 0pt}
        }{%
            \hyperlink{exercises2}{\customhead{6}{Exercises}}%
        }
        \adjustbox{
            set depth=2pt,
            padding={5pt 5pt 5pt 5pt},
            rndframe={color=navigationTileOutline,width=1pt}{3pt 0pt 3pt 0pt},margin={10pt 0pt 0pt 0pt}
        }{%
            \hyperlink{tables}{\customhead{7}{Tables}}%
            \hspace{5pt}$ \cdot $\hspace{5pt}%
            \hyperlink{finishingnotes}{\customhead{8}{Finishing notes}}%
        }%
        \hfil
        Slides available at texnicie.nl
        \hfil
        \vskip4pt
    \end{beamercolorbox}%
    \begin{beamercolorbox}[colsep=1.5pt]{lower separation line head}%
    \end{beamercolorbox}%
}