There are lots of command lines which can be used with the Google Chrome browser. Some change behavior of features, others are for debugging or experimenting. This page lists the available switches including their conditions and descriptions.
Selenium cannot reliably control a browser when its window is not in focus, or when you accidentally interact with the browser frame. This will result in flickering tests, which are "randomly" red and green. In fact, this behavior is not random at all and completely depends on whether or not the browser window had focus at the time. This card will give you a better understanding of Selenium focus issues, and what you can do to get your test suite stable again.
What I always find hardest to figure it when it comes to unknown systems, it’s ‘how things fit together’. These project might have great documentation, but how the ecosystem plays together is usually left as an exercise for the reader. This happened to me again when diving into frontend testing. I figured out how to get nightwatch+selenium-standalone+chromedriver+chrome working somehow, without fully understanding each part in the puzzle. I went with Nightwatch because I like the syntax and it seems one of the obvious options nowadays. That works until I updated some dependencies and broke everything again. So I took some time to figure out how these things fit together and what is really needed for me tests. I’ve learned that Selenium is the godmother of modern frontend testing. It’s a framework with bindings for multiple languages. To decouple the server from the actual browsers, it invented “Selenium RC” as a protocol. That lead to the development of the WebDriver W3C standard which replaces Selenium RC is newer versions and is implemented for the most common browsers (Chrome -> Chromedriver, Firefox -> FirefoxDriver).
If your test suite handles a modal dialog popup, for example, a redirect to another location, then you may need to add a custom profile so that the popup is suppressed. This can be fixed by applying a custom Firefox profile with the option turned off: (example is in Ruby using Capybara)