Open a scenario that uses data from local cache
Delete the scenario with the view still open
Clear cache

MAEviz will report that it could not delete the dataset, but it happily deletes the properties file so it no longer exists in local cache. Those datasets left behind will never be deleted by local cache, even if you create a new scenario with a new file generated and placed in local cache. Clearing local cache will only clear the new file since the other files don't have properties files associated with them anymore so MAEviz doesn't know they exist.

We should warn the user that some files are still in use and cannot be deleted and don't delete the props file unless the dataset can be deleted as well.