Can't search by timestamp value in topic message viewer

[derek1ee]

1. Open a topic with messages
2. Pick an existing message, and copy the timestamp value
3. Ensure timestamp column is in UNIX time format
4. Paste the timestamp into search textbox

Expected:
The message is filtered and shown with timestamp highlighted
(Ideally, even if I don't do step 3 and the timestamp is in ISO format, it still produce a match when search by UNIX time and vise versa).

Actual:
Search doesn't appear to search against timestamp column, no search result is shown.