I developed a small utility app which has one NSWindow. I usually put it on Desktop 2 (IIRC it was called workspace? But it seems Apple doesn’t do it any more), but when I rebooted the OS, it went to show on Desktop 1, which is a bit annoying. I had failed to find the solution throughout Apple documents and random experiments (well, it turned out I have lame search skill).

• Autosave name property of NSWindow in Interface Builder saves the frame across the app launches, but not the Desktop across OS launches.

• Programmatically using setFrameUsingName works the same way.

  Actually, the property that work for it is NSWindow’s isRestorable, settable in Interface Builder as Restorable in the Behavior section of NSWindow.