Thank you Marg7. I have failed. Tools/Options/Advanced ok but no "Network & Disc Space".
I downloaded "about config" from your " click here". Unfortunately "Tools" does not contain "Add-ons". Do I have a faulty Thunderbird?
Hands-on: Samsung Galaxy S8 review
1995-2015: How technology has changed the world in 20 years
Samsung's beautifully designed Galaxy S8 makes for better VR experiences too
47 iPhone camera tips to help you take better photos
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.