Using Joomla! 1.5.15, I have created a number of articles in the same category. I then created a menu item and linked it to Category List Layout and linked to this category, and when I clicked on the link on the frontend it displayed a list of the articles as expected.
I then created some more articles but in a different category, created another menu item and also selected Category List Layout and linked to this category. When I checked in the frontend there was no list of articles. I then check the previous menu item and it is now also blank.
If I change either menu item to any other type, e.g. Category Blog Layout, all the articles diplay correctly.
After digging for ages I eventually found the solution although a small issue of the chache obsured the result initially.
I entered the menu item in question and then under the Parameters (Components) I had to turn on the Category Title and also make it linkable. Initially this didn’t make any difference until I cleared my Cache and then all displayed correctly.