Opt-in per account feature to keep the session/signin-state between app restarts

[vladimiry]

Right now the app doesn't keep the session/cookies/signin-state between restarts since the account's sessions are intentionally stored in memory only so each time the app gets started the signing process gets performed (the process is automated though). But we could store the specific cookies in encrypted settings.bin so then when the user restarts the app there will only be a need to enter the master password to be signed-in into the protonmail account (see settings.bin purpose in FAQ).

[vladimiry]

The feature released in https://github.com/vladimiry/ElectronMail/releases/tag/v4.2.0.

[vladimiry]

Showing how to enable the feature for the specific email account (image picked from v4.2.0):

[vladimiry]

Picking feature description from v4.2.0 and FAQ:

This is an opt-in and per account feature. You might want to try this feature if you like the convenience of automated login into the email accounts but don't want to keep the credential in the app settings (the settings.bin file is encrypted, see file purpose in the FAQ). The feature enables the scenario when you enter the account credentials on the login form only once, preferably manually as it's more secure not to save the credentials anywhere, and then you won't see the login form anymore for this email account even if you restart the app. Having enabled the feature you can verify that the same proton-session is reused by going to the /settings/security admin area section in your account.

So if this feature is enabled for the account, manual credentials filling is the preferred option as a more secure option since you don't save the account credentials anywhere (credentials are encrypted though even if saved, see settings.bin file description in the FAQ).