As far as we can determine, the value passed to SetNetworkProxy() is persisted by LexActivator; if you restart your app and do not call SetNetworkProxy(), the previous value still holds. Note that it would be very helpful if the documentation reflected this.
It appears that you can reset the network proxy setting by passing an empty string to SetNetworkProxy(). Does that restore automatic proxy detection? Put another way, how can you specify that no proxy should be used? If you do that by setting the network proxy to an empty string, then how can you restore automatic proxy detection? Again, it would be very helpful to have this in the documentation.