NSTrackingSeparatorToolbarItem causes problems when putting a window in full screen on Golden Gate (macOS 27)

Update July 20: Developer beta 4 seems to fix this. NSTrackingSeparatorToolbarItem adds a white band over the top of the leading split view panes when in full screen mode on macOS 27. That white band appears to have the height of the toolbar. I have a sample project that demonstrates the issue. To reproduce it: Download and open the sample project . Observe that the main window contains a simple…