diff --git a/src/backend/macos/file_dialog/panel_ffi.rs b/src/backend/macos/file_dialog/panel_ffi.rs
index fe722b8..83bb3f3 100644
--- a/src/backend/macos/file_dialog/panel_ffi.rs
+++ b/src/backend/macos/file_dialog/panel_ffi.rs
@@ -66,7 +66,7 @@ impl Panel {
 
     pub fn run_modal(&self) -> i32 {
         if let Some(parent) = self.parent.clone() {
-            let completion = { block::ConcreteBlock::new(|_: u32| {}) };
+            let completion = { block::ConcreteBlock::new(|_: isize| {}) };
 
             unsafe {
                 msg_send![self.panel, beginSheetModalForWindow: parent completionHandler: &completion]
diff --git a/src/backend/macos/message_dialog.rs b/src/backend/macos/message_dialog.rs
index 586d1cc..b75dd63 100644
--- a/src/backend/macos/message_dialog.rs
+++ b/src/backend/macos/message_dialog.rs
@@ -10,7 +10,7 @@ use super::{
     AsModal,
 };
 
-use super::utils::{INSWindow, NSWindow};
+use super::utils::{INSApplication, INSWindow, NSApplication, NSWindow};
 use objc::runtime::Object;
 use objc::{class, msg_send, sel, sel_impl};
 use objc_foundation::{INSString, NSString};
@@ -104,7 +104,13 @@ impl NSAlert {
 
     pub fn run(mut self) -> MessageDialogResult {
         if let Some(parent) = self.parent.take() {
-            let completion = { block::ConcreteBlock::new(|_: u32| {}) };
+            let completion = {
+                block::ConcreteBlock::new(|result: isize| {
+                    let _: () = unsafe {
+                        msg_send![NSApplication::shared_application(), stopModalWithCode: result]
+                    };
+                })
+            };
 
             unsafe {
                 msg_send![self.alert, beginSheetModalForWindow: parent completionHandler: &completion]