Hi Martin,
Uikit is developed by Yootheme, not us :), its open source and we use Uikit for our particles.

About the issue: Do you mean Base Outline or special outline that you created before ?
IMO: Just create a hidden menu item for the PARENT category only, for this case, it should be BLOG. Because all sub categories and articles inherited from the blog parent, why you need to create the “Links to Gantry5 Outline “Blog”” ?

Could you please submit a private ticket with your site info so I can take a close look the blog structure settings?