There is a gadget/macro in Confluence called "Projects" - it creates a list of multiple projects. The gadget can be configured to return a specified selection of projects or a list of projects by category.

However neither of the drop down lists for Projects or Categories are returning the full list of projects/categories in our instance. I'm seeing the Projects list returning 53 of 90 projects (plus the All Projects option) and the Categories list returning 8 of 16 categories (plus the All Categories option).
I can't see any commonality as to why some of the projects or categories might be excluded by the gadget/macro.
The missing projects are also reflected when the gadget/macro is inserted, so when a category is chosen the list returned is missing projects.
Can anyone explain why some projects/categories are missing? Is there any way around this?