This is a recurring issue here. Even with experienced user, users aware of the problem and users willing to reply to the thread (me included) happen to create a new thread instead of replying to the existing one.
As it is, the reply-GUI is confusing and that fact that this issue is widespread is proof of it.
Please fix, "reply to thread" and "create new thread" GUIs look too similar.
I don't know how you could fix this. One way could be to remove the "New thread" interface at the bottom and add a floating "+ Add" button in the bottom right corner.
I agree that this is a big issue and probably the issue that spawned this idea:
https://microsoftteams.uservoice.com/forums/555103-public/suggestions/16930585-drag-chat-messages-to-merge-them-into-one-reply-th
This is a recurring issue here. Even with experienced user, users aware of the problem and users willing to reply to the thread (me included) happen to create a new thread instead of replying to the existing one.
As it is, the reply-GUI is confusing and that fact that this issue is widespread is proof of it.
Please fix, "reply to thread" and "create new thread" GUIs look too similar.
I don't know how you could fix this. One way could be to remove the "New thread" interface at the bottom and add a floating "+ Add" button in the bottom right corner.
Regards