Browser Not Opened Exception

com.kms.katalon.core.webui.exception.BrowserNotOpenedException
I’m getting this error when using a firefox derivative browser.
This works:
FirefoxDriver driver = new FirefoxDriver(options);
driver.get(url)

The browser opens, the page is loaded, but any subsequent action gives a browser not opened exception.

So I guess when the browser is opened it is not being registered with some core Katalon class??

(See answer, though it seems to be running dog slow.)

ANSWER:
I dug into the source classes and found I could do this:

com.kms.katalon.core.configuration.RunConfiguration.storeDriver( driver )

which makes the driver available to Katalon Studio.