onRowExpanded  
  fun onRowExpanded(connectFlags: <Error class: unknown class> = ConnectFlags(0u), handler: (iter: TreeIter, path: TreePath) -> Unit): <Error class: unknown class>(source)
The given row has been expanded (child nodes are shown).
Parameters
connectFlags 
a combination of ConnectFlags
handler
the Callback to connect. Params: iter the tree iter of the expanded row; path a tree path that points to the row