This must be due to the selector you are using. I have tried this inside Open Browser and it works both with and without the Attach Browser activity. Please see the attached file which opens the browser assigns it to a variable uiBrowser and then clicks Chelsea on the BBC Football website. The attach window activity is disabled but maybe using that will help you, notice it uses the uiBrowser variable (type=Browser) to attach to the window that was previously opened by the Open Browser activity.