Delete is handled differently in 0.5; Geary will warn you before deleting a message.  It's also not the default operation, Geary offers Trash instead.

However, we could offer a way to Trash or Delete individual messages.  I'm thinking the option would go in the message drop-down menu and the right-click context menu.  Because conversations don't include messages in the Trash, either operation should remove the message from the conversation.  However, if the user Trash/Deletes all the conversation's messages in the current folder, then the entire conversation will disappear.

The lack of this option is especially problematic, because drafts are shown as part of their related conversation, wich makes it impossible to delete it, without deleting the other messages too. Renaming the mail or changing the adress is not helping as a workaround either. At least, that is what I thought would happen.

After trying it with an unimportant email, I recognized, that the described behaviour is NOT shown, but the dialogues IMPLY that it's going to happen (as it's not only a deletion button for the shown full conversation, but the confirmation dialogue is also asking about "messages" in plural, even though it only deletes the draft, wich is one.)

So clarification would be great :)

I have submitted bug 732331 for the described problem with drafts (wich is also a problem in trash folders).

bug 714674 seems to be quite similar to this bug here. The only difference is, that it's refering to the overall possibility and not to the interface-wise design problems.

I think that bug 714674 can be merged into this issue.
The ability to delete a single message can be useful, for example in case of thread hijacking.

*** Bug 714674 has been marked as a duplicate of this bug. ***

*** Bug 735048 has been marked as a duplicate of this bug. ***

*** Bug 761751 has been marked as a duplicate of this bug. ***

I've been wondering about this bug (which I wouldn't really call a bug) for quite some time now. The lack of the feature to delete a single mail in a thread is the one and only reason that's keeping me from using this client. I love everything else about it!

Are you planning on implementing this feature in a near future?

It shouldn't be too hard to implement the actual trashing/deletion, but some extra work may need to be taken to ensure the message is removed from the conversation in a responsive way. However, since the way the UI works is changing significantly due to Bug 765516, there's not much point implementing this until that lands (which isn't too far off).

I'm not sure what the use-case is for per-message archiving, however. If you archive a message, it should remain in the conversation after being moved, and hence there won't be any visible change as a result. What am I missing?

*** Bug 772207 has been marked as a duplicate of this bug. ***

This isn't going to make it for 0.12 (unless someone can contribute a patch over the next few days), so bumping to 0.13.

Can a feature like this be left out waiting for the complete redesign planned with bug 792388

Remove bugs from 0.13 with dependencies on others.

I've just pushed commit 6c8bc2c5 to master that implements trashing and deleting in-folder messages in a conversation, courtesy work done by Alex Henrie. This will be released in 0.13.

Some additional work is still needed to make this happen for out-of-folder messages, and despite the title I'm not sure if it's worth implementing this for archiving/junk/user-created folders since we probably want a different UI for that, but I think Alex's impl will take care of a the main uses-cases for the moment, so I'm going to resolve this as fixed.

NB: See https://gitlab.gnome.org/GNOME/geary/issues/93 for support for out-of-folder support.