Loading the Terminator project onto PyCharm for the last issue I raised notified me of a lot of PEP style problems but more importantly, I found a bug:
prefseditor.py:

    def on_backspace_binding_combobox_changed(self, widget):
        """Backspace binding setting changed"""
        selected = widget.get_active()
        if selected == 1:
            value = 'control-h'
        elif selected == 2:
            value = 'ascii-del'
        elif selected == 3:
            value == 'escape-sequence'
        else:
            value = 'automatic'
        self.config['backspace_binding'] = value
        self.config.save()

If you select Escape Sequence it fails to apply the option and save the config. It's a simple case of fat fingers putting a double = and turning an assignment into an evaluation.
Are there any cleanup/style or other tasks that I could help with? In that same file, there is an apparently superfluous import of GObject, but I'd rather not touch that yet.