The GUI still shows the same behavior: After saving the configuration and reloading the LT-settings, the remote server option is still selected but the URL seems to be lost
BUT
A network trace shows that my remote server is used for spell checking. As soon as I start typing, TCP 8081 packets are sent to the remote server located within my network and the spell check is properly executed!
So, it just seems to be related to the add-on’s graphical interface.
Thank you for helping me out. If there’s anything I can contribute, just let me know!