在使用Python2.7+Selenium3.0.2+Firefox50.1時，鼠標事件ActionChains運行總是報錯，報錯信息如下：
C:\Python36\python3.exe C:/Users/root/PycharmProjects/untitled3/test170117.py
Traceback (most recent call last):
File "C:/Users/root/PycharmProjects/untitled3/test170117.py", line 458, in <module>
ActionChains(driver).move_to_element(set).perform()
File "C:\Python36\lib\site-packages\selenium\webdriver\common\action_chains.py", line 74, in perform
action()
File "C:\Python36\lib\site-packages\selenium\webdriver\common\action_chains.py", line 225, in <lambda>
Command.MOVE_TO, {'element': to_element.id}))
File "C:\Python36\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 236, in execute
self.error_handler.check_response(response)
File "C:\Python36\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 192, in check_response
raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: POST /session/3ba988a1-5c6f-4999-8815-71d40e62a6af/moveto did not match a known command
經過搜索，說是geckodriver和Firefox有Bug,最后將Selenium3.0.2換成Selenium2.53.0（此時環境為Python2.7+Selenium2.53.0+Firefox50.1），此時運行python腳本時，報錯：
報錯信息忘了截圖了？？？？？
搜索后，說是因為Selenium支持Firefox及其以下版本，所以最后環境變為：Python2.7+Selenium2.53.0+Firefox46，問題解決，ActionChains（）類下的各種鼠標操作方法完美運行。
github上該Bug相關信息：
https://github.com/SeleniumHQ/selenium/issues/2285
https://github.com/mozilla/geckodriver/issues/159