I created a Feedback for this issue FB22645938

With iOS 26.4, a white space has now appeared above the side navigation toolbar. But only when using NavigationSplitView within TabView. I hope this gets fixed; otherwise, I’ll have to write a custom TabView. Things had been quiet for a while, but now it’s annoying me again.

Hi Becca, thank you very much! I hope the problem will be solved soon, otherwise I see no other way to rebuild the NavigationSplitView. The sidebar of the TabView is not sufficient for my needs, as I have to use a highly customized view here.

The spacing issue is back since 18.4. Any suggestions?

I had the same problem, if you have the NavigationSplitview in a NavigationStack, then you should remove it and put the NavigationStack in the detail area.