Hey, thanks for the report. This is a known bug in 2.6.11. It’s related to the Editor Classic layout.
Workaround: click the double-arrow icon in the top-right corner of the chat panel to switch away from the Classic layout. After that, chat history should work normally.
More details in this thread: [2.6.11] Clicking On Chat in Chat History Not Working
The team is aware of the issue. Let me know if the workaround doesn’t help.