Prevent a Combobox from scrolling in PyGTK

combo.py

def combo_scrolling(combobox, event):
    """Prevent the comboboxes from scrolling."""
    combobox.emit_stop_by_name("scroll-event")


values = ['item 1', 'item 2', 'item 3']
combo = gtk.combo_box_new_text()

# Fill with part type options
for val in values:
    combo.append_text(val)
                
# Set default selection to first field
combo.set_active(0)

combo.connect("scroll-event", combo_scrolling)

Thank you