"New Posts" function doesn't work in all forums !!

[The-PaperBird]

Hello all, i'm new & this is my first post

Alright , i searched & found threads regarding "new post" problems, but couldn't find my exact question.
It's like this: the new post function doesn't work in all forums, in another meanin, it works only in forums that i posted in, & forums that had new topics while i wasn't there.
In some forums, i can see from the date & time (in "last posts" column) that there is new posts, but its not blinking !! i noticed that it happens with forums that i didn't post in <--- at least since the last time i've been there (cuz i'm the admin, i've postsed in all categories & forums)

Can this be changed or its meant to be that way ?

Some other details:
*i checked the url of the new posts icon, its good.
*i tried in both IE & FF, the same thing.
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There's a lil thing that i don't understand, which i think it has sth to do with what i'm asking above:
What's the difference between these 2 icons?
*forum - new post
*category - new post

I know what's the difference between a forum & a category, but....well, i 'll apreciate if you make things clear for me

I hope my question is clear, i also hope i posted in the right forum

Thank you.

[The-PaperBird]

Nobody heard of this before ??