Currently, information for Contacts entries can be read and edited only from a single view. This means that data can be inadvertently changed or deleted without warning; there is no possibility to undo changes or deletions.
Please consider introducing an explicit Edit mode, which requires acceptance of changes ('Okay' or 'Save') and allows any changes made to be cancelled ('Cancel') or reverted to previously stored version ('Undo').
@DeepDiver1975 Should feature requests for Apps are also discussed here or should they be moved to github?
There is an issue open for this here:
github com owncloud contacts issues 459
(Can't post the link due to starter member limitations)
I opened the thread here to try to gain a wider audience of Users (rather than only addressing the devs).
It seems that a dissenting voice on Github results in the locking of the issue to collaborators only, which doesn't help the discussion.
(Should this be in Development/Apps, as Contacts is a core function now.)
Well, at the end some one needs to implement it. 
This is not correct. The contacts app (where you're requesting an separate read and edit function) is a 3rdparty app not shipped with core. Only the CalDAV and CardDAV functionality is included in core.
If you're referring to https://github.com/owncloud/contacts/issues/255 it seems this was locked because everything what needs to be discussed was already discussed.
Ah, yes – sorry. I shouldn't have doubted you! 
Well, maybe.
@RealRancor No, apparently everything that needs to be discussed has not been discussed. It has not been resolved. And although that thread #255 is still going, it's just been locked to us. Two developers are discussing at this very minute the matter on there, rather than here, having locked the thread and told us to start one in the forums. They haven't even commented on the forum thread that was created.
@olantrust Well, feel free to discuss such a simple one button thingy to death in here. The guys discussing that at the bugtracker are the one which needs to implement this (as long as no one of you here is doing it. 
). And they need to make decisions not for only a few users but for the whole functionality of the Contacts App. Unfortunately that's how it is working. 
Edit When reading through the linked issue one can see that it was locked because it was originally discussed how to handle the PO box topic and then was hijacked by a few user to discusss a separate view / edit mode which is a new topic. Thats why @jancborchardt asked you guys to create a new thread / issue about this new topic.