解决：selenium在chrome上运行报 Element is not clickable at point
问题
Firefox上正常运行的脚本在chrome上提示Element is not clickable at point。
分析原因，首先肯定不是因为页面元素不存在而无法点击。也不是要点击的button不在预览范围内。
后来发现，是被前一步的操作的一个弹出层挡住了。因为前一步是弹出了一个list层，在关闭list的时候webdriver就立刻执行下一步点击这个元素（element）时，而这时list可能还没完全关闭掉。
解决办法是等待那个弹出层完全关闭掉，元素（element）可以点击的时候再执行
# 添加客户账户
Wait Until Element Is Visible %{U_WEB_STOCK_ADD_CUSTOMER_BTN}
Click Element %{U_WEB_STOCK_ADD_CUSTOMER_BTN}
Wait Until Element Is Visible %{U_WEB_STOCK_ADD_CUSTOMER}
Input Text %{U_WEB_STOCK_ADD_CUSTOMER} ${customer}
# 点击弹出层
Click Element %{U_WEB_STOCK_CHOOSE_MANAGER}
${mng_element} Self_Defined_Variable ${manager}
Click Element ${mng_element}
Capture Page Screenshot
# 等待弹出层完全关闭掉
sleep %{U_WEB_WAITING_TIME}
${submit_element} Self_Defined_Variable 提交
Click Element ${submit_element}
Wait Until Element Is Not Visible %{U_WEB_STOCK_ADD_CUSTOMER_SUBMIT}
Capture Page Screenshot 等待直到定位的元素可以点击
至于FF上可以正常运行，是selenium支持的更好些。
具体原因：
“The reason for the element is not clickable at point(x,y) exception.
Some of my observation was
- It mostly happens in Chrome so if you are mostly working with Firefox or IE then you will not be getting this exception.
- Chrome does not calculate the exact location of element
- Chrome always click in the middle of Element.
- Sometimes you will get this exception due to Sync issue also.”