I can Create New Folder by clicking on a Mate or Part in a stack of the same, and it will create a Folder with that Part or Mate, but its not letting me add any others to that Folder. Does this even with simple test Assemblies. Does it after shut down and reboot and re-start of Solidworks. Use to always work fine, with light blue U-shaped arrow that would allow adding to Folder from above or below