Battle Cup tier chat join button missing

[flehma]

Windows 10 Dota 2

• System information from steam (Steam -> Help -> System Information) in a gist: No need for that.
• Have you checked for system updates?: Yes
• Are you using the latest stable video driver available for your system? Yes
• Have you verified the game files?: Yes

Please describe your issue in as much detail as possible:

There once was a button to join a battle cup chat for a specific region and tier. But it went missing or I am just stupid enough to not find it.

Steps for reproducing this issue:

1. Open Dota
2. Open Battle Cup
3. Search for a button to join a Chat