This actually seems to work..?

src/lib.rs

@@ -389,6 +389,6 @@ where
     }
 }
 
-pub fn hack() {
-    crate::native::apple::apple_util::startup_hack();
+pub fn prevent_double_click_bug_on_macos() {
+    crate::native::apple::apple_util::prevent_double_click_bug_on_macos();
 }

src/native/apple/apple_util.rs

@@ -569,54 +569,34 @@ pub extern "C" fn yes1(_: &Object, _: Sel, _: ObjcId) -> BOOL {
 static mut HACKED: bool = false;
 
 pub fn define_app_delegate_class() -> *const Class {
-    println!("Defining app delegate!");
-
     let superclass = class!(NSObject);
     let mut decl = ClassDecl::new("MyAppDelegate", superclass).unwrap();
 
     unsafe {
-        decl.add_method(
-            sel!(applicationShouldTerminateAfterLastWindowClosed:),
-            yes1 as extern "C" fn(&Object, Sel, ObjcId) -> BOOL,
-        );
         decl.add_method(
             sel!(applicationDidUpdate:),
             application_did_update as extern "C" fn(&Object, Sel, ObjcId),
         );
     }
 
-    extern "C" fn application_did_update(this: &Object, _: Sel, _: ObjcId) {
+    extern "C" fn application_did_update(_this: &Object, _: Sel, _: ObjcId) {
         unsafe {
             if !HACKED {
                 HACKED = true;
-                println!("Application did update, delegate was called!");
-
-                let psn = ProcessSerialNumber {
-                    a: 0,
-                    b: WhichProcess::kCurrentProcess as u32,
-                };
-
-                let os_status: i32 = TransformProcessType(
-                    std::ptr::addr_of!(psn),
-                    TransformProcess::kProcessTransformToForegroundApplication as u32,
-                );
-
-                println!("os_status: {}", os_status);
-
-                let ns_app: ObjcId = msg_send![class!(NSApplication), sharedApplication];
-                let () = msg_send![ns_app, activateIgnoringOtherApps: YES];
+                let current_application: ObjcId =
+                    msg_send![class!(NSRunningApplication), currentApplication];
+                let _: BOOL = msg_send![current_application, activateWithOptions: nil];
             }
         }
     }
 
     return decl.register();
 }
 
-pub fn startup_hack() {
+pub fn prevent_double_click_bug_on_macos() {
     unsafe {
         let app_delegate_class = define_app_delegate_class();
         let app_delegate_instance: ObjcId = msg_send![app_delegate_class, new];
-
         let ns_app: ObjcId = msg_send![class!(NSApplication), sharedApplication];
         let () = msg_send![ns_app, setDelegate: app_delegate_instance];
     }

src/native/apple/frameworks.rs

@@ -94,31 +94,6 @@ extern "C" {
     pub fn NSLog(fmt: ObjcId, ...);
 }
 
-#[repr(packed)]
-pub struct ProcessSerialNumber {
-    pub a: u32,
-    pub b: u32,
-}
-
-#[repr(i32)]
-pub enum WhichProcess {
-    kNoProcess = 0,
-    kSystemProcess,
-    kCurrentProcess,
-}
-
-#[repr(i32)]
-pub enum TransformProcess {
-    kProcessTransformToForegroundApplication = 1,
-    kProcessTransformToBackgroundApplication = 2,
-    kProcessTransformToUIElementApplication = 4,
-}
-
-#[link(name = "ApplicationServices", kind = "framework")]
-extern "C" {
-    pub fn TransformProcessType(psn: *const ProcessSerialNumber, transformState: u32) -> i32;
-}
-
 #[link(name = "ImageIO", kind = "framework")]
 extern "C" {
     pub static kUTTypePNG: ObjcId;