SmartDiagram overlapping text

Question

I am using SmartDiagram with an additional module in a figure environment. However the additional module is being drawn outside the bounds of the figure environment:

How do I get the figure so it does not overlap the text?

Here is the current code I have:

\documentclass{article}
\usepackage{smartdiagram}
\usesmartdiagramlibrary{additions}
\begin{document}
Some lines of text: these should be above the diagram.
\begin{figure}[h]
    \centering
    \smartdiagramset{
     circular distance=36mm,
     text width=35mm,
     module minimum width=35mm,
     module minimum height=15mm,
     module shape=rectangle,
     arrow tip=to,
     uniform arrow color=true,
     arrow color=gray!50!black,
     border color=black,
     uniform color list=white for 6 items,
     additions={
       additional item offset=15mm,
       additional item text width=35mm,
       additional item height=15mm,
       additional item shape=rectangle,
       additional item border color=black,
       additional item shadow=drop shadow,
       additional arrow color=gray!50!black,
     }
    }
    \smartdiagramadd[circular diagram:clockwise]{
            {Second Box (2)}, 
            {Third Box (3)}, 
            {Fourth Box (4)}, 
            {Fifth Box (5)}, 
            {Sixth Box (6)}
        }{
            above of module1/{First Box (1)
        }
    }
    \smartdiagramconnect{-to}{additional-module1/module1}   
    \caption{Example diagram.}
\end{figure}
\end{document}

Answer 1

The additions are added in a separate tikzpicture environment which uses the options remember picture, overlay. Consequently, these items do not update the bounding box, as explained on page 7 of the manual. The suggestion there is to use a minipage. However, in this case, it seems just as easy to do without.

Rather than use the h specifier, I'd use a center environment and \captionof, if a caption is required. That is, if you really do not want the figure to float. If you do want it to float, if necessary, then simply use figure with \centering as in your original example.

Either way, you need to manually leave space for the additional module in the diagram. For example:

\documentclass{article}
\usepackage{smartdiagram,capt-of}
\usesmartdiagramlibrary{additions}
\begin{document}
Some lines of text: these should be above the diagram.
\begin{center}
  \vskip 30mm\par
  \smartdiagramset{
    circular distance=36mm,
    text width=35mm,
    module minimum width=35mm,
    module minimum height=15mm,
    module shape=rectangle,
    arrow tip=to,
    uniform arrow color=true,
    arrow color=gray!50!black,
    border color=black,
    uniform color list=white for 6 items,
    additions={
      additional item offset=15mm,
      additional item text width=35mm,
      additional item height=15mm,
      additional item shape=rectangle,
      additional item border color=black,
      additional item shadow=drop shadow,
      additional arrow color=gray!50!black,
    }
  }
  \smartdiagramadd[circular diagram:clockwise]{
    {Second Box (2)},
    {Third Box (3)},
    {Fourth Box (4)},
    {Fifth Box (5)},
    {Sixth Box (6)}
  }{
    above of module1/{First Box (1)
    }
  }
  \smartdiagramconnect{-to}{additional-module1/module1}
  \captionof{figure}{Example diagram.}
\end{center}
\end{document}

produces