Some applications are either bugged or configured by the developer to never stop looking for updates. For this application, it's necessary to have an Internet connection because it retrieves various data from the online servers. In some cases they're called "always on applications". They're apps that depend entirely on Internet in order to function properly.
To try to overcome this issue, firstly launch it as Administrator. This procedure will give you the possibility to save the text you added to the application. Secondly, use Windows Firewall and block it permanently from accessing the Internet. This way you will stop it from accessing Internet all the time.
When you will have an Internet connection, simply turn off the Firewall or remove it from the blocking list.