Found another one, just next to the time I posted this you can see the re: Topic title ecc that gets truncated as well...
I'd suggest to put overflow: visible;
max-width: 100%;
instead of the original overflow: hidden;
max-width: 15em;
for .post_subject. It should show up correctly on all resolutions and auto-align correctly, due to the small font there shouldn't be any problems with that.