read icons are not showing on some browses

a few of my moderators reported this because they use View unanswered posts • View unread posts • View new posts • View your posts • View active topics options and when they click back to whatever they were looking at, please dont say this is not a bug because my other forum that is not phpbb went back fine saying it been read on firefox and chrome

the first time i posted this bug i went to firefox support live i said i may have found a bug on firefox i give them my test account the bloke went onto my forum and saw the problem himself he said it was a phpbb3 gecko code problem or whatever it is