The Activity Stream Gadget with username filter does not work, and will be empty for some users.
I am getting user IDs by opening JQL, typing `assignee = users` and copy and pasting the numberical ID that appears there when a user's name shows up, you click that user, and it auto-inserts the ID. In the JQL here, the search works correctly.
However, in the Activity Stream Gadget with the username filter, only some usernames will work - the ones with shorter IDs. The ones that have a `smallernumber:largernumber` format do not work.