but when i scroll ten at a time, it does not show those messages i read in that mode [by changing the color of the post in the list}
That's something I've looked into before, and it's not really addressable easily or without a ton of overhead from what I've come up with so far.
The problem is that it's your browser that determines whether or not a URL has been visited before. And if you're reading messages in a batch view, you're not visiting the URLs for the individual messages.