I took notice of your suggestions for my plugin. Some of them were not on my radar when I started writing it, and they seem like a nice addition. I'll think about them and see what I can do about them.
I've tested again my plugin with Category Visibility iPeat Rev. I think I didn't find anything wrong with the two plugins working together. Anyway, reading your comments more carefully I noticed that you mention something about sticky posts on your blog not being shown anymore. I assumed that you have an additional plugin which allows you to create sticky posts and which interferes with Post Groups -- but I'm not sure which one was it.
So, what I did was to install one of the sticky-related plugins and see what happens. I've chosen WP-Sticky for this, and I believe I now have the solution for making all these plugins work together.
Thanks for letting me know about these incompatibilities. I took extra care that my patches won't work only when having Category Visibility and WP-Sticky installed -- that is, I think I made my plugin work with any other plugins that might reorder posts. This is true when navigating my groups: the posts order within a group is what one expects when having other post-reordering plugins activated.
The only problem is on the front page -- by design, here I need to show one single post from each group (some kind of featured post from each group). But which post? I'm showing the latest post from each group, but this would be different when having WP-Sticky activated. I'm also considering a redesign of this feature.
It's not too late to tell me what other plugins you have activated on your blog (and maybe what theme are you using).
Anyway, I'm ready for a new release today. My plugin is a little bit more improved, thanks to the bugs reported by lionel_chollet, and I'm confident it'll work (well, until the next bug that is reported :-)
Funny thing is, the previous version was released on July 1 (Canada Day). This last version will be released today, July 4, US Day... I think I'll call them like this: Canada Day Release, and US Independence Day Release :-)
I hope there is no major bug in this release, so that I won't need to have a sooner-than-expected Venezuela Day Release (July 5).