Only solution I've been able to work out on this is when you create the project (or edit it after it's created) to have the paths listed in the order you want to see them. For example, I have
Workspace - nothing listed
Local Search Paths - nothing listed
Workgroup Search Paths
- Workgroup (for my current project work)
- Another Path (named and pointing to a folder from which I am borrowing/copying parts)
Library Search Paths
- Library (pointing to our standard library of fasteners, etc).
I've found that whatever order the paths are shown on the "Project" creation page, that is the order shown on the "Open" page.