Last days I've been working in a python module to recreate a dual listbox widget using Gtk3, and here it is.
To sum up the whole code, I've extended a Gtk.Box widget and added the needed extra widgets in it (buttons and treeviews). Also added some useful methods (set new content, clear a list, etc).
To use the widget, just import the dual_listbox module and create an object, like this:
myList = dual_listbox.DualListBox('column1 name', 'column2 name')
Here you can check the code and here It's a working example. Comments and questions are welcomed ;)
