Perhaps I've munged this beyond hope since I'm using several category plugins, samecat by David Chait, Category Visibility by Keith McDuffee, and Post Templates by Category by Kaf Oseo (Kafkaesqui on this forum).
These are all working fine in two other categories I've set up. We have the President's Message and Member Profiles. When you click on the sidebar link (which is the category link), the category-x.php template kicks in and displays post excerpts and at the very bottom, David Chait's samecat plugin, which displays all the posts in that same category. Works fine for Prez Message and Member Profiles.
I'm trying to set it up for Tech Tips, too, but this may be a sticky issue because Tech Tips is a parent category that has several child categories (e.g., Engine and Drivetrain, Performance Mods, etc.). When I created the first Tech Tip article, I put it in the parent (Tech Tips) and child (Engine and Drivetrain) categories.
It displays fine in the category-10.php template, EXCEPT that David Chait's plugin doesn't seem to want to display. And I get "No posts matched your criteria" when I click on the permalink for the individual entry.
Here's the site:
Update: I CHECKED [x] front on the Tech Tips category in the Category Visibility Plugin and it's working fine now, but I really didn't want the Tech Tips on the front page. As long as the archive checkbox is checked off, it should work fine, right? Hmm. Maybe there's a way to exclude the category (10) and its children (11-15) from the front page some other way?
(Check out the Site Information in the footer, where I've given props to all the great plugin writers!!)