GtkTreeView - connecting nodes by lines

[Vladimir Lapacek <vol0za centrum cz>]

Hello, 

I have a question relating to the GtkTreeView rendering. I have tried to
search the answer in lists and google, but from the answers I was unable
to produce desired result.

GtkTreeView uses small triangles to show the tree. However, for a large
tree structure it would be better to see the explicit connections
between related nodes (like in QT, Windows, ...). I was unable to find
any option to display the connection lines in the GtkTreeView.  I do not
have any experience with GtkCellRenderer, but I assume, that neither
this way it can be done. All answers suggested that this is theme
specific feature (all tree-views should behave the same way).

Can you point out some theme, which contains this feature (nodes of the
tree-view are connected by lines) or more preferably how can I create
such theme?

If there is some documentation or disscusion about this topic, I would
like to read it.

Thanks,
        Vladimir Lapacek