Customize/extend the window draggable area of your Mac Catalyst app.

UIResponder+performWindowDrag.swift

//
//  UIResponder+performWindowDrag.swift
//  JonnyUtility
//
//  Created by Jonny Kuang on 10/7/19.
//  Copyright © 2019 Junyu Kuang <lightscreen.app@gmail.com>. All rights reserved.
//

import UIKit

public extension UIResponder {
    
    /// Call this method inside a `UIResponder.touchesBegan(_:with:)` method to perform window drag.
    ///
    /// This method has effect only when your app is running on macOS.
    func performMacCatalystWindowDrag() {
        // NSApplication.shared.currentEvent
        // NSWindow.performDrag(with:)
        
        #if targetEnvironment(macCatalyst)
        guard let nsApp = ((NSClassFromString("NSApplication") as? NSObject.Type)?.value(forKey: "sharedApplication") as? NSObject),
            let currentEvent = nsApp.value(forKey: "currentEvent") as? NSObject,
            let nsWindow = currentEvent.value(forKey: "window") as? NSObject else { return }
        nsWindow.perform(NSSelectorFromString("performWindowDragWithEvent:"), with: currentEvent)
        #endif
    }
}


/* example
private class DraggableNavigationBar : UINavigationBar {

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        performMacCatalystWindowDrag()
        super.touchesBegan(touches, with: event)
    }
}
*/

Have you figured out how to disable the default drag behavior?