Possible issue with Chromedriver 78, Selenium can not find web element of PDF opened in Chrome

I've run into the same issue.

Apparently Chrome automatically updates itself. Yesterday (Oct 29 '19) My ChromeDriver started complaining that it was not compatible with Chrome 78. I updated the driver to the 78 version. I started to get random org.openqa.selenium.NoSuchElementException exceptions when trying to find elements that I confirmed were there. The findElement[s] also work when I used breakpoints. I also tried implicit waits, with only limited success.

I tried zsbappa's ChromeOption solution but no joy.

Google makes it hard to get old versions of Chrome, but I found version 76 at https://www.neowin.net/news/google-chrome-76-offline-installer/. Beware, the online installer installs the latest version. I reverted to the driver for 76 and all is good. All my Selenium tests are working again.

My conclusion is that the Chrome 78 and it's associated driver has a race condition where Selenium attempts to interrogate the web page before it's complete.

We have faced a similar issue with Chrome 78.0.3904.7, Chromedriver 77/78, Python Selenium 3.141.0.

In our automated Python Selenium tests, we've seen multiple failures where it appears that clicks on elements have not occurred. Even stranger, it appears that the element has become active (as if it were about to be clicked) but the the actual click event never occurred. As a result, page switches etc do not occur resulting in various downstream failures.

By a process of trail and error, we found that using the standard .click() function is now not reliable:

webdriver_element.click()

But using Action Chains does appears to be reliable:

ActionChains(context.browser).click(webdriver_element).perform()

It's not clear why this is the case. The failures began as soon as we upgraded to Chrome 78.0.3904.7. We're using Chromedriver 77.0.3865.90 but the same tests pass reliably on Chrome 77.x versions therefore it appears something is wrong or has changed in Chrome 78.