In my MWE :
- why
line width=0ptdoesn't work ? - why the dashed argument on a level leeks on the next ?

\documentclass[tikz]{standalone}
\usetikzlibrary{trees}
\begin{document}
\begin{tikzpicture}[level distance=5mm,
level 1/.style={sibling distance=32mm,line width=0pt},
level 2/.style={sibling distance=16mm,dashed},
level 3/.style={sibling distance=8mm,level distance=12mm},
%level 4/.style={sibling distance=7mm},
%every fit/.style={rectangle,draw,inner sep=3.5pt},
grow=right]
\scriptsize
\node {$\bullet$}
child {node {P}
child {node{PP}
child {node{PPP}}
child {node{PPF}}
}
child {node{PF}
child {node{PFP}}
child {node{PFF}}
}
}
child {node {F}
child {node{FP}
child {node{FPP}}
child {node{FPF}}
}
child {node{FF}
child {node{FFP}}
child {node{FFF}}
}
} ;
\end{tikzpicture}
\end{document}
