/*!
\page free_nodes_page Free nodes
\n This mesh quality control highlights nodes which are not connected
to any mesh element. Free nodes are shown with a color differs from
the color of nodes.
\image html free_nodes.png
In this picture some nodes don't connected to a mesh element as
a result of deleting elements and adding several isolated nodes.
See Also a sample TUI Script of a
\ref tui_free_nodes "Free Nodes quality control" operation.
*/