Currently, hiding an app is implemented by setting the rowId to the negative number, so it can be reversed later by again multiplying it by -1.
However, this seems to break Launchpads app ordering.
Solution: Do not set the rowId to a negative number. Instead, delete the row completely. In order to be able to unhide the item, we have to remember it somewhere (own database?).
I normally have the first Launchpad page (with the Apple suite) and my second page with all my installed applications.
However, shortly after a fresh install of Launchpad-Control, I end up with a 3rd and empty launchpad page before my Apple suite page. It doesn't show up in the Launchpad-Control options, and the only way I've found to get rid of it is to re-install Launchpad-Control.