The question is – do we abandon and remove it.
Firstly it is important to understand how ‘new post’ handling is performed for forum members. This process is described in detail on the wiki. This process is used everywhere with the exception of the new post icon n the forum index of the Group View.
The reason it is not used in this view is because the members ‘new post list’ only holds the topic ids. Yes – it would be possible to display the forum index row and work out from the users list if any of the topics in the list belong to the forum but that is a very slow, query intensive procedure which will have a noticeable and unwanted negative effect on performance. This is especially true of you have a lot of forums and/or a large topic list.
It is also possible to add the forum id to the users new post list. This is the ideal solution and has only been rejected for 4.2 because it involves some serious code changes that would delay the release. It can be re-considered for 4.3.
So how does it currently work?
When the forum index row is displayed we do have available to us the timestamp of the last post made in any topic belonging to that forum. This is compared to the last visited date of the user. Quite simply, if the last visited date is before the last topic post date then the icon is displayed. initially, at the time of login, this is accurate. But as a few people have pointed out if the user then visits that forum and reads the topics that were unread when they return to the Group View the icon is still shown. This is because the last Visited date remains the same for the session – as it needs to.
So the icon – signifying unread posts – can become inaccurate during a users forum session. This is not ideal and, as stated above, we can overcome this. But as we do not have the time to replace this code in 4.2, the question is do we just remove the functionality until such a time as we can get it right or do we leave it in for 4.2 as it is better, perhaps, than nothing. I made the suggestion to remove it simply because it is a question that seems to come up fairly often.
(Additional note for James: When we were discussing this the other day the problem was exacerbated by incorrect processing of the timestamp on posts. This, we believe, is probably a bug introduced into WP in, perhaps 2.9.1. We have now fixed that which at the very least means that the icon resets itself upon logout/login or timeout of the users session.)
