"Latest Posts" widget problem when posts are in same category

On a site I built for a friend, the “Latest Posts” widget displays the latest posts properly. But if I click on a title of a post that is in a category with more than one post, rather than taking me just to the post I clicked on, it takes me to a page with ALL the posts, in their entirety (with comments) for that category. If the post I clicked on doesn’t happen to be the most recent post in that category, I have to scroll all the way down the page to find the post I originally clicked on. Is there some option I don’t know about? How can I make it so when you click on a post, it just takes you to that post?

Thanks!