Hide Filter won't stay

I'm trying to hide a particular folder by going into Folder Options for the parent folder, then to Filters, then adding the folder's name to the Folders portion of the Hide Filter section.

When I click OK the folder gets hidden, but after restarting DOpus the folder is visible and the filter is reset.

How can I get it to stick?

Use the Save button at the top of the Folder Options window.