Opened files list has changed:
        --> open/close file action
        --> modification ('*' added to title)
        --> current edited file has changed

def opened_files_list_changed(self):
        """
        Opened files list has changed:
        --> open/close file action
        --> modification ('*' added to title)
        --> current edited file has changed
        """
        # Refresh Python file dependent actions:
        editor = self.get_current_editor()
        if editor:
            python_enable = editor.is_python()
            cython_enable = python_enable or (
                programs.is_module_installed('Cython') and editor.is_cython())
            for action in self.pythonfile_dependent_actions:
                if action in self.cythonfile_compatible_actions:
                    enable = cython_enable
                else:
                    enable = python_enable
                if action is self.winpdb_action:
                    action.setEnabled(enable and WINPDB_PATH is not None)
                else:
                    action.setEnabled(enable)
            self.open_file_update.emit(self.get_current_filename())