I have changed the topic tag to app:web-vault, since that is the app you are using.
If you change the generator settings (e.g., Length) in the Tools > Generator screen, it should remember those settings when you use the generator function (
) in the item editor.
Why are you using the Web Vault app to perform these tasks? I would suggest that you read the advice that I gave about the Web Vault and other apps in another recent thread: