The Halon style (and maybe some other too but saw it only with this style) cuts displayed texts if the text is a little longer (try "This is a beginning of a beautiful friendship. This is a beginning of a beautiful friendship." for example) if (and only then!) also an icon is applied to the notification.
Having seen this from MozillaSnarls / FireSnarl as well as from Snarl_CMD.exe.
Have a thread in my forum at http://tlhan-ghun.de/?q=node/778 (more to the end) including a screenshot)