[PyGObject] TreeView: edit a cell like in excel

[<c buhtz posteo jp>]

I want to make the user renaming text-items in a Gtk.TreeView.
Like you would do in a GUI-file-manager when pressing F2.

I mean the edit-field (Gtk.Entry?) should be layed over the item itself
while editing.

Is this possible?

I tried (On Linux, XFCE, with Gtk3.0) Gtk.TreeView.set_cursor_on_cell()
what is not fully working.
 - The item is selected but no edit-field appears.
 - The edit-field appears only if I hit a button on keyboard.
 - The edit-field is not on the same position as the item. It is at the
   end of the TreeView.