diff --git a/CHANGELOG.md b/CHANGELOG.md
index a10bcf72..0e28f803 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,7 @@
 - Add `PartialEq`, `Eq`, and `Hash` implementations on public types that could have them but were missing them.
 - On X11, drag-and-drop receiving an unsupported drop type can no longer cause the WM to freeze.
 - Fix issue whereby the OpenGL context would not appear at startup on macOS Mojave (#1069).
+- **Breaking:** Removed `From<NSApplicationActivationPolicy>` impl from `ActivationPolicy` on macOS.
 
 # Version 0.17.2 (2018-08-19)
 
diff --git a/src/os/macos.rs b/src/os/macos.rs
index 776c10ff..a0470ede 100644
--- a/src/os/macos.rs
+++ b/src/os/macos.rs
@@ -1,8 +1,6 @@
 #![cfg(target_os = "macos")]
 
-use std::convert::From;
 use std::os::raw::c_void;
-use cocoa::appkit::NSApplicationActivationPolicy;
 use {LogicalSize, MonitorId, Window, WindowBuilder};
 
 /// Additional methods on `Window` that are specific to MacOS.
@@ -47,19 +45,6 @@ impl Default for ActivationPolicy {
     }
 }
 
-impl From<ActivationPolicy> for NSApplicationActivationPolicy {
-    fn from(activation_policy: ActivationPolicy) -> Self {
-        match activation_policy {
-            ActivationPolicy::Regular =>
-                NSApplicationActivationPolicy::NSApplicationActivationPolicyRegular,
-            ActivationPolicy::Accessory =>
-                NSApplicationActivationPolicy::NSApplicationActivationPolicyAccessory,
-            ActivationPolicy::Prohibited =>
-                NSApplicationActivationPolicy::NSApplicationActivationPolicyProhibited,
-        }
-    }
-}
-
 /// Additional methods on `WindowBuilder` that are specific to MacOS.
 ///
 /// **Note:** Properties dealing with the titlebar will be overwritten by the `with_decorations` method
diff --git a/src/platform/macos/window.rs b/src/platform/macos/window.rs
index 10939f73..c982e94a 100644
--- a/src/platform/macos/window.rs
+++ b/src/platform/macos/window.rs
@@ -16,6 +16,7 @@ use cocoa::appkit::{
     NSWindow,
     NSWindowButton,
     NSWindowStyleMask,
+    NSApplicationActivationPolicy,
 };
 use cocoa::base::{id, nil};
 use cocoa::foundation::{NSAutoreleasePool, NSDictionary, NSPoint, NSRect, NSSize, NSString};
@@ -718,7 +719,15 @@ impl Window2 {
             if app == nil {
                 None
             } else {
-                app.setActivationPolicy_(activation_policy.into());
+                let ns_activation_policy = match activation_policy {
+                    ActivationPolicy::Regular =>
+                        NSApplicationActivationPolicy::NSApplicationActivationPolicyRegular,
+                    ActivationPolicy::Accessory =>
+                        NSApplicationActivationPolicy::NSApplicationActivationPolicyAccessory,
+                    ActivationPolicy::Prohibited =>
+                        NSApplicationActivationPolicy::NSApplicationActivationPolicyProhibited,
+                };
+                app.setActivationPolicy_(ns_activation_policy);
                 app.finishLaunching();
                 Some(app)
             }