selenium with IE: click button to download the file, and then clicks other buttons, the process will be stuck

Question

By using selenium with IE 11 and Python 3.6.3, need to download Excel and PDF files from Website with selenium：

1. click download button
2. send keys S to save file
3. click other button to download

When I execute the third step, my code was stuck without any exception.

Key Code:

def _click_excel(self):

    for i in range(self.retry_times):
        try:

            self.wait.until(EC.element_to_be_clickable((By.LINK_TEXT, 'Excel Download'))).click()
            return ErrCode.add(ErrCode.SUCCESS)

        except Exception as err:
            logger.error("statement  error：{}".format(err))

    return ErrCode.add(ErrCode.CURRENT_MENU_HAS_CHANGED, "statement  error")

def _send_save_keys():
    # send  ALT + S 

    # statements

def _click_view(self, item, inner_height):
    for i in range(self.retry_times):
        try:

            xpath = '//a[@id="rq{}"]'
            self.wait.until(EC.element_to_be_clickable((By.XPATH, xpath.format(item)))).click

            return ErrCode.add(ErrCode.SUCCESS)

        except Exception as err:
            logger.error("statement  error：{}".format(err))

    return ErrCode.add(ErrCode.CURRENT_MENU_HAS_CHANGED, "statement  error")