我仍然不知道真正的解决方案，但是这是我正在使用的肮脏解决方法：

public static void Click(this IWebElement element, TestTarget target)
{
    if (target.IsInternetExplorer)
    {
        var actions = new Actions(target.Driver);
        actions.MoveToElement(element).Perform();
        Thread.Sleep(500); // wait for the mouseover popup to appear
        element.SendKeys(Keys.Escape); // to close the popup (if any)
        actions.MoveToElement(element).DoubleClick().Perform(); // simple click is sometimes not enough in IE
    }
    else
    {
        element.Click();
    }
}