Q: Using pre opened window with Selenium I am trying to get Selenium WebDriver to find and use a browser window that is already open before the script executes.  I am writting in Java.
I am using selenium-server 2.37.0 and the browser is IE8.  I am open to using the Chrome browser as well.
Anyway, I have tried opening a driver instance and then looking for the window handles in the usual way (Set handles = driver.getWindowHandles();) but this only finds the hadle of the window that the driver opened.  I have also just tried to switchTo the window by the window cannot be found.
The reason I want to use a pre-opened window is because when I execute my script, for some reason the browser won't let it click a link (It may be because the link is to an https address and sends a username and a token).  When the script finishes the webpage won't respond to me manually clicking the link either.
I am able to manualy navigate to the link and click it the link works fine, so my thinking is that I can navigate to the page that I want and then kick of the scripts from there, but I need the webdriver to use this browser window that I used.
I cannot navigate the to link directly with Selenium because the link resided behind a secure server.  I have to log in first then click the link and this is where I am having the problem.

A: Unfortunately, as of 2.37.1 (December 2013), it cannot be done.
There is an official feature request for this in the Selenium project (and it's even the most starred one), but it has not been done yet.

A: You can identify a browser window by windowHandle and switch between several Windows while testing.
You can print out all existing windowHandles (in your case it might be one) and then access it.
This solution worked for me (using Selenium 3.4.0):
Object[] handles = driver.getWindowHandles().toArray();
String windowHandle = handles[0]+"";
driver.switchTo().window(windowHandle);

After switching to your browser window you should be able to continue your test.
It relys on correctness of your webdriver- if you opened an Edge window the driver you use should be an EdgeDriver. 
