A suggestion, as the title says. Often times i click on a thread in the new posts section, with a catching title and am ever so slightly infuriated about the fact that i can't reply. Yes it is a rare occurance this happens, but for those times i think something should be done about it
Are those threads from some groups? It's not possible to disable not-public groups from showing up in that list without fiddling with the forum core files (which is generally not a good idea)