App does not prevent accidental leave that causes data loss

[ChristophWurst]

Steps to reproduce

1. Compose a new message
2. Before draft saving kicks in, close the tab

Expected behavior

The app asks me for confirmation and only drops my data if I consent.

Actual behavior

Data is silently dropped.

Mail app version

No response

Mailserver or service

No response

Operating system

No response

PHP engine version

No response

Web server

No response

Database

No response

Additional info

This can be solved by JavaScript's onbeforeunload.

[thstyl2000]

It's actually even more troublesome in the following case:

1. Start writing an email.
2. Draft is saved for the first time. "Draft saved" notification is shown.
3. Continue writing for some time. "Draft saved" notification is continuously shown.
4. Remember sth you need to check from another email.
5. You close the editor directly.
6. You lose your last couple of sentences because the email is saved periodically.