Thanks for reaching us out.
Please note that you are referring to a post from over an year ago. In the context of browsers which are being constantly updated, improved and even completely changed as structure I would recommend to submit new issue and provide specific details for the currently experienced misbehavior.
Anyways, I suppose you are not using the latest unified extension distributed for Firefox which is designed to use the latest Firefox APIs. As of the 57th version of the browser the old extensions will be no longer supported. Please review the details listed here
- double check the current versions of Test Studio and FF you have and upgrade these accordingly if necessary.
Please note that Chrome also has a new extension released as of Test Studio R3 release (v.2017.3.1010) - here
is the respective information.
I hope this will be useful to you. In case of further queries do not hesitate to contact us again. Thanks!