Highlitted topics thingy

difficult to explain but here we go.
when logging in you have the highlighted/coloured icons on the side to indicate new threads/posts (with me so far?)
I then go to look at one post then click to read or look at new new thread and there no longer highlighted not just the odd one the whole site :x
really annoying I then just log off cause I cant be bothered at having to look at dates to see if there new or not!
Just ruins the experiance for me, this is the only forum that does it to me I,ve cleared cookies I have even looked at forum through IE8 and it does it there also :shock:
Paul