This is really important.. :)

I really enjoy this feature in other mail programs like Outlook and Gmail. I use whether a message is read as an indicator for whether I should take additional action.

So being able to set the "Mark as Read" time to 20 secs, for example, would be very helpful.

Yes, this is a simple but interesting idea. Mark as read does not mean that the mail received the appropriate action. It only means that the mail has been opened on my screen - and that does not mean a thing.

I would like this as well.

Here is a reddit post that describes this in more detail:

https://www.reddit.com/r/ProtonMail/comments/r4qaic/feature_request_do_not_automatically_mark_emails/

I practice 0 inbox principle, and I use the same hack to highlight important message with action to be done, in contrast with read message still inbox as reminder.
So I would be very nice to be able to NOT automatically mark as read when opened. This setting could be add, like in Thunderbird.

I would agree. This is a privacy feature as it doesn't notify the sender that you have read the message especially sales tactics, etc.

Click on the email. There is an eye with a slash through it just to the left of the Label icon. Click that and the email becomes unread. I wish I knew how to do this for multiple emails at once.

Add config option to NOT automatically mark the opened message as read.

This feature can be set on the swipe settings under settings--for both android and ios. Not sure about browsers.

Very similar request:
- https://protonmail.uservoice.com/forums/284483-feedback/suggestions/13000893-swipe-feature-to-include-read-unread

This is possible by now.

i have a weird problem that my messages become marked as "unread" when I log back in, but only sometimes, I have bad feeling perhaps email is hacked? does anybody have a clue on this "feature"? I also like to mark only certain emails as unread so I can return to them, but I have been very disappointed at the status of my messages (inbox and sent box)being strangely re-set to "un read" this is very unsettling

I'd like to be able to mark messages as "unread" after reading them. This helps me know which messages I need to return to later or that I've started reading but haven't had time to finish. Many other webmail services have this feature