On a browser settings when one selects firefox as the browser application a proxy tab is added. When you go to the proxy tab everything is grayed out so you cannot select a proxy, what is the purpose of this tab if you can't set the proxy? It would be nice if I could define different proxy settings per device connection.
Could you try out the latest RDM beta version? I recall there was an issue with this that was fixed in one of the beta updates.
Regards,
Hubert Mireault