Two issues related to `Replying to:...` UI

[SebinSong]

Problem

[1]
Replying to: ... UI isn't cleared when switching to another chatroom:

replying-to-issue.mp4

[2]
When a mention popup is open while replying to a message, the replying-to UI overlaps the mention pop-up:

Especially, when there is only one user to show in the mention list, this makes it look like no pop-up is being displayed at all.

Solution

Fix