NavigationSplitView window resize problem

When the application window is resized (horizontally or vertically) or maximized to full screen, the navigationSplitView within the app does not resize with it and looks like a broken UI with all three views sticking to the center and not filling the entire screen how do we handle this? Ideally would like to have the experience of apps like notes and xCode etc. When the app window is resized, the navigation system within the app correctly resets to the window. Any help is appreciated