Empty space/row in FolderTree between root elements

Hello there
image
What are those empty rows between root elements in folder tree? Is there any way to remove them?
Jacek

Preferences -> Folder Tree -> Appearance

Unchecking Separate items at the root level may be what you want.
However, left checked, you can still separate them with a custom pixel spacing.

Unchecking 'Separate items at the root level' did help, indeed. Thanks a lot.