FBWF: feature? cannot commit new directories

[Guest]

I have been trying to commit files using the Api/fbwfmgr.

Commits for files like this work
C:\Test1.txt

But as soon as I want to commit a file in a NEW directory (C:\Test), e.g.
C:\Test\Test1.txt

I get "Fbwfmgr failed: Incorrect Function"

for the directory itself
C:\Test (or C:\Test\)

I get "Fbwfmgr failed: The system cannot find the file specified."

However: fbwfmgr /overlaydetail shows the directory/file

The Api documentation says "terminated wide string containing the file or
directory" so I assumed it should be possible to commit (new) directories?

But it seems this is only possible to commit EXISTING directories i.e. only
directories created BEFORE activating the filter? Did not find ANY hint about
this in the documentation???

=> there is no way to add new directories without rebooting?
=> Bug or feature???