Comment 11 for bug 750139

I've got crash to day and found something what may be related:

    def on_window_halign_value_changed(self, halign_button):
        """Changes the value of window_halignment in gconf
        """
        if halign_button.get_active():
            which_align = {
                'radiobutton_align_left': ALIGN_LEFT,
                'radiobutton_align_right': ALIGN_RIGHT,
                'radiobutton_align_center': ALIGN_CENTER
            }
            self.settings.general.set_int(
                'window-halignment', which_align[halign_button.get_name()]
            )
        self.prefDlg.get_widget("window_horizontal_displacement").set_sensitive(
            which_align[halign_button.get_name()] != ALIGN_CENTER
        )

The issue is with which_align which is assumed to be always present but won't be if first if will be false