Thank you for evaluating Test Studio.
Currently Test Studio only allows recording in IE. You can execute in IE, Firefox, Safari and Chrome, but you can only record in IE. We've had a few customers request to be able to use alternative browsers and it is on our to-do list for someday.
You can try to change the "User Agent" string that IE sends. This makes the web server believe it's communicating with Firefox instead. See below for examples.
: We have not tested this method nor can we support it. We simply offer it as a potential work-around if you absolutely require this implementation.
the Telerik team