Nope, there's still that whitespace pushing over the right. In fact, in my searches, I've come across this topic:
viewtopic.php?f=26&t=28596
That outlines the same issue. It's suggested at the end there may be a bugfix, but the main phpBB boards are down now, so I'll have to wait and see...
There is NOTHING more maddening that coding CSS for IE6...
NOTHING.