I have a simple gtk.TreeView with a gtk.ListStore model and set_reorderable(True), I want to catch the signal/event emited when the user reorder through drag&drop the list, but the documentation does not help much: 
"The application can listen to these changes by connecting to the model's signals"
So I tried to connect the model (ListStore) signals... but surprise! ListStore has no signals, so you are dispatched to TreeModel signals, then I tried to connect with the TreeModel "rows-reordered" signal with no lucky.
How should I catch the list reorder performed by the user?
There is no way to do that in PyGTK currently.  "rows-reordered" is the correct signal, but it is impossible to derive any information from it in PyGTK other than "somehow reordered".  In C GTK+ you could use the same signal and get the required information in callback, but not in Python.
Catch PyGTK TreeView reorder