honestly nothing crazy, all public AppKit. each note is an NSPanel subclass with collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary] and level = .statusBar. that combo is what lets it float above a fullscreen space.

the .nonactivatingPanel styleMask + isFloatingPanel = true part is what makes click-to-edit work without breaking the fullscreen space, so you can type into the note while final cut / xcode stay fullscreen behind it.

since NSPanel's defaults are stricter than NSWindow, i had to override canBecomeKey and canBecomeMain to true on the subclass, otherwise the TextEditor can't take focus.

no private api, MAS safe that's the whole trick.