Clicking the suggestion box with @user_names doesn't work when the @user_name is not going to be the first token in the comment (which may happen when I want to notify a user while talking to another user or to general public (example)).
When I click the suggestion box, it goes bold, but the name is not inserted in the comment, and a js error occurs:
nullor not an object
Pressing Tab in this situation works as expected. Only clicking does not work.