Messages in threads are lost

[BenWiederhake]

Steps to reproduce:

• Be person A, have your client open from the beginning
• Person B writes a message
• Person C responds to that message in a "thread"

Expected result: Both messages should appear in the chat somehow. It's fine if the thread-context is lost. (Or even better, there is at least some marker [Thread 123456] or something.)

Actual result: Person C's message does not get displayed, and is effectively lost. (Note that I can see Person B's message just fine.)