diff --git a/src/macos/view.rs b/src/macos/view.rs
index 35a9445..87c9d11 100644
--- a/src/macos/view.rs
+++ b/src/macos/view.rs
@@ -14,10 +14,7 @@ use objc::{
 };
 use uuid::Uuid;
 
-use crate::{
-    Event, MouseButton, MouseEvent, Point, WindowHandler,
-    WindowOpenOptions
-};
+use crate::{Event, MouseButton, MouseEvent, Point, WindowOpenOptions};
 use crate::MouseEvent::{ButtonPressed, ButtonReleased};
 
 use super::window::{
diff --git a/src/macos/window.rs b/src/macos/window.rs
index 5b00674..25613f5 100644
--- a/src/macos/window.rs
+++ b/src/macos/window.rs
@@ -59,7 +59,7 @@ impl Window {
         options: WindowOpenOptions,
         build: B
     ) -> (crate::WindowHandle, Option<crate::AppRunner>)
-        where H: WindowHandler,
+        where H: WindowHandler + 'static,
               B: FnOnce(&mut crate::Window) -> H,
               B: Send + 'static
     {
diff --git a/src/x11/window.rs b/src/x11/window.rs
index 93d153f..e44cbec 100644
--- a/src/x11/window.rs
+++ b/src/x11/window.rs
@@ -223,7 +223,7 @@ impl Window {
     }
 
     #[inline]
-    fn drain_xcb_events<H: WindowHandler>(&mut self, handler: &mut H) {
+    fn drain_xcb_events(&mut self, handler: &mut dyn WindowHandler) {
         // the X server has a tendency to send spurious/extraneous configure notify events when a
         // window is resized, and we need to batch those together and just send one resize event
         // when they've all been coalesced.
@@ -252,7 +252,7 @@ impl Window {
     // FIXME: poll() acts fine on linux, sometimes funky on *BSD. XCB upstream uses a define to
     // switch between poll() and select() (the latter of which is fine on *BSD), and we should do
     // the same.
-    fn run_event_loop<H: WindowHandler>(&mut self, handler: &mut H) {
+    fn run_event_loop(&mut self, handler: &mut dyn WindowHandler) {
         use nix::poll::*;
 
         let xcb_fd = unsafe {
@@ -291,7 +291,7 @@ impl Window {
         }
     }
 
-    fn handle_xcb_event<H: WindowHandler>(&mut self, handler: &mut H, event: xcb::GenericEvent) {
+    fn handle_xcb_event(&mut self, handler: &mut dyn WindowHandler, event: xcb::GenericEvent) {
         let event_type = event.response_type() & !0x80;
 
         // For all of the keyboard and mouse events, you can fetch