Description:

Cannot mention other users after newline in message

Server Setup Information:

• Version of Rocket.Chat Server: 0.62.1
• Operating System: Ubuntu 16.04.3 LTS
• Deployment Method(snap/docker/tar/etc): Snap
• Number of Running Instances: 1
• DB Replicaset Oplog: Enabled
• Node Version: v8.8.1
• mongoDB Version: ?

Steps to Reproduce:

1. Start writing message in channel
2. Add newline with ctrl-enter
3. Start writing @ to mention oser

Expected behavior:

A list of users should be visible

Actual behavior:

Nothing happens, the @ sign appears by itself without the user list appearing