Extra unwanted space in main window

Hi there! I'm having this issue with my main windows. I'm having a big space on top of that without any logic explanation (at least for my poor knowledge).

Using the code below I'm getting this Windows layout:

Does anybody have any guidance on how to get out that extra space at the beginning?

Thanks a lot!

import SwiftUI
import SwiftData
#if os(macOS)
import AppKit
#endif

// Helper to access and control NSWindow for size/position persistence
#if os(macOS)
struct WindowAccessor: NSViewRepresentable {
    let onWindow: (NSWindow) -> Void
    func makeNSView(context: Context) -> NSView {
        let view = NSView()
        DispatchQueue.main.async {
            if let window = view.window {
                onWindow(window)
            }
        }
        return view
    }
    func updateNSView(_ nsView: NSView, context: Context) {
        DispatchQueue.main.async {
            if let window = nsView.window {
                onWindow(window)
            }
        }
    }
}
#endif

@main
struct KaraoPartyApp: App {
    @StateObject private var songsModel = SongsModel()
    @Environment(\.openWindow) private var openWindow
    var body: some Scene {
        Group {
            WindowGroup {
                #if os(macOS)
                WindowAccessor { window in
                    window.minSize = NSSize(width: 900, height: 700)
                    // Configure window to eliminate title bar space
                    window.titleVisibility = .hidden
                    window.titlebarAppearsTransparent = true
                    window.styleMask.insert(.fullSizeContentView)
                }
                #endif
                ContentView()
                    .environmentObject(songsModel)
            }
            .windowToolbarStyle(.unifiedCompact)
            .windowResizability(.contentSize)
            .defaultSize(width: 1200, height: 900)
            .windowStyle(.titleBar)
            #if os(macOS)
            .windowToolbarStyle(.unified)
            #endif

            WindowGroup("CDG Viewer", id: "cdg-viewer", for: CDGWindowParams.self) { $params in
                if let params = params {
                    ZStack {
                        #if os(macOS)
                        WindowAccessor { window in
                            window.minSize = NSSize(width: 600, height: 400)
                            // Restore window frame if available
                            let key = "cdgWindowFrame"
                            let defaults = UserDefaults.standard
                            if let frameString = defaults.string(forKey: key) {
                                let frame = NSRectFromString(frameString)
                                if window.frame != frame {
                                    window.setFrame(frame, display: true)
                                }
                            } else {
                                // Open CDG window offset from main window
                                if let mainWindow = NSApp.windows.first {
                                    let mainFrame = mainWindow.frame
                                    let offsetFrame = NSRect(x: mainFrame.origin.x + 60, y: mainFrame.origin.y - 60, width: 800, height: 600)
                                    window.setFrame(offsetFrame, display: true)
                                }
                            }
                            // Observe frame changes and save
                            NotificationCenter.default.addObserver(forName: NSWindow.didMoveNotification, object: window, queue: .main) { _ in
                                let frameStr = NSStringFromRect(window.frame)
                                defaults.set(frameStr, forKey: key)
                            }
                            NotificationCenter.default.addObserver(forName: NSWindow.didEndLiveResizeNotification, object: window, queue: .main) { _ in
                                let frameStr = NSStringFromRect(window.frame)
                                defaults.set(frameStr, forKey: key)
                            }
                        }
                        #endif
                        CDGView(
                            cancion: Cancion(
                                title: params.title ?? "",
                                artist: params.artist ?? "",
                                album: "",
                                genre: "",
                                year: "",
                                bpm: "",
                                playCount: 0,
                                folderPath: params.cdgURL.deletingLastPathComponent().path,
                                trackName: params.cdgURL.deletingPathExtension().lastPathComponent + ".mp3"
                            ),
                            backgroundType: params.backgroundType,
                            videoURL: params.videoURL,
                            cdfContent: params.cdfContent.flatMap { String(data: $0, encoding: .utf8) },
                            artist: params.artist,
                            title: params.title
                        )
                    }
                } else {
                    Text("No se pudo abrir el archivo CDG.")
                }
            }
            .windowResizability(.contentSize)
            .defaultSize(width: 800, height: 600)

            WindowGroup("Metadata Editor", id: "metadata-editor") {
                MetadataEditorView()
                    .environmentObject(songsModel)
            }
            .windowResizability(.contentSize)
            .defaultSize(width: 400, height: 400)

            WindowGroup("Canciones DB", id: "canciones-db") {
                CancionesDBView()
            }
            .windowResizability(.contentSize)
            .defaultSize(width: 800, height: 500)

            WindowGroup("Importar canciones desde carpeta", id: "folder-song-importer") {
                FolderSongImporterView()
            }
            .windowResizability(.contentSize)
            .defaultSize(width: 500, height: 350)
        }
        .modelContainer(for: Cancion.self)
        // Add menu command under Edit
        .commands {
            CommandGroup(replacing: .pasteboard) { }
            CommandMenu("Edit") {
                Button("Actualizar Metadatos") {
                    openWindow(id: "metadata-editor")
                }
                .keyboardShortcut(",", modifiers: [.command, .shift])
            }
            CommandMenu("Base de Datos") {
                Button("Ver Base de Datos de Canciones") {
                    openWindow(id: "canciones-db")
                }
                .keyboardShortcut("D", modifiers: [.command, .shift])
            }
        }
    }

    init() {
        print("\n==============================")
        print("[KaraoParty] Nueva ejecución iniciada: \(Date())")
        print("==============================\n")
    }
}