Editing username field from an account with no issuer exits edit screen

**Describe the bug:** If I have an account with a username and no issuer and I:

1. click edit,
2. cut the username (using either Ctrl+X or right-click) or select and delete it,

it immediately saves the change and exits the edit screen, leaving an unidentifiable account with no issuer or username.

If I backspace through the username, it saves and exits before I delete all of the text.

This behaviour doesn't happen if I add text to the username, and then cut/delete/backspace the username.

**Platform:**
- Browser: Firefox
- Browser Version: 76.0.1