REQUEST: Hide [xbs] *empty* folders

[cipitaua]

I'm syncing between firefox and chromium, and I've organized my bookmarks so that the special folders are empty:

The presence of the empty [xbp] folder prevents the hiding of the "Tutti i preferiti" ("All bookmarks") folder, which would free up space in the bookmark bar.

I think the [xbs] folder should be created only when needed, and removed otherwise.