diff --git a/crates/fj-app/src/main.rs b/crates/fj-app/src/main.rs
index 3dca6df06..283efecc7 100644
--- a/crates/fj-app/src/main.rs
+++ b/crates/fj-app/src/main.rs
@@ -91,7 +91,7 @@ fn main() -> anyhow::Result<()> {
     let invert_zoom = config.invert_zoom.unwrap_or(false);
 
     let watcher = model.load_and_watch(parameters)?;
-    run(Some(watcher), shape_processor, status, invert_zoom)?;
+    run(watcher, shape_processor, status, invert_zoom)?;
 
     Ok(())
 }
diff --git a/crates/fj-interop/src/status_report.rs b/crates/fj-interop/src/status_report.rs
index 23f74b802..f5c645da2 100644
--- a/crates/fj-interop/src/status_report.rs
+++ b/crates/fj-interop/src/status_report.rs
@@ -3,6 +3,7 @@
 use std::collections::VecDeque;
 
 /// Struct to store and update status messages
+#[derive(Default)]
 pub struct StatusReport {
     status: VecDeque<String>,
 }
@@ -10,9 +11,7 @@ pub struct StatusReport {
 impl StatusReport {
     /// Create a new ``StatusReport`` instance with a blank status
     pub fn new() -> Self {
-        Self {
-            status: VecDeque::new(),
-        }
+        Self::default()
     }
 
     /// Update the status
@@ -39,9 +38,3 @@ impl StatusReport {
         self.status.clear();
     }
 }
-
-impl Default for StatusReport {
-    fn default() -> Self {
-        Self::new()
-    }
-}
diff --git a/crates/fj-window/src/run.rs b/crates/fj-window/src/run.rs
index 31194880f..000fc9b67 100644
--- a/crates/fj-window/src/run.rs
+++ b/crates/fj-window/src/run.rs
@@ -27,7 +27,7 @@ use crate::window::{self, Window};
 
 /// Initializes a model viewer for a given model and enters its process loop.
 pub fn run(
-    watcher: Option<Watcher>,
+    watcher: Watcher,
     shape_processor: ShapeProcessor,
     mut status: StatusReport,
     invert_zoom: bool,
@@ -49,50 +49,48 @@ pub fn run(
     event_loop.run(move |event, _, control_flow| {
         trace!("Handling event: {:?}", event);
 
-        if let Some(watcher) = &watcher {
-            match watcher.receive_shape(&mut status) {
-                Ok(shape) => {
-                    if let Some(shape) = shape {
-                        match shape_processor.process(&shape) {
-                            Ok(shape) => {
-                                viewer.handle_shape_update(shape);
-                            }
-                            Err(err) => {
-                                // Can be cleaned up, once `Report` is stable:
-                                // https://doc.rust-lang.org/std/error/struct.Report.html
+        match watcher.receive_shape(&mut status) {
+            Ok(shape) => {
+                if let Some(shape) = shape {
+                    match shape_processor.process(&shape) {
+                        Ok(shape) => {
+                            viewer.handle_shape_update(shape);
+                        }
+                        Err(err) => {
+                            // Can be cleaned up, once `Report` is stable:
+                            // https://doc.rust-lang.org/std/error/struct.Report.html
 
-                                println!("Shape processing error: {}", err);
+                            println!("Shape processing error: {}", err);
 
-                                let mut current_err = &err as &dyn error::Error;
-                                while let Some(err) = current_err.source() {
-                                    println!();
-                                    println!("Caused by:");
-                                    println!("    {}", err);
+                            let mut current_err = &err as &dyn error::Error;
+                            while let Some(err) = current_err.source() {
+                                println!();
+                                println!("Caused by:");
+                                println!("    {}", err);
 
-                                    current_err = err;
-                                }
+                                current_err = err;
                             }
                         }
                     }
                 }
-                Err(err) => {
-                    // Can be cleaned up, once `Report` is stable:
-                    // https://doc.rust-lang.org/std/error/struct.Report.html
+            }
+            Err(err) => {
+                // Can be cleaned up, once `Report` is stable:
+                // https://doc.rust-lang.org/std/error/struct.Report.html
 
-                    println!("Error receiving updated shape: {}", err);
+                println!("Error receiving updated shape: {}", err);
 
-                    let mut current_err = &err as &dyn error::Error;
-                    while let Some(err) = current_err.source() {
-                        println!();
-                        println!("Caused by:");
-                        println!("    {}", err);
+                let mut current_err = &err as &dyn error::Error;
+                while let Some(err) = current_err.source() {
+                    println!();
+                    println!("Caused by:");
+                    println!("    {}", err);
 
-                        current_err = err;
-                    }
-
-                    *control_flow = ControlFlow::Exit;
-                    return;
+                    current_err = err;
                 }
+
+                *control_flow = ControlFlow::Exit;
+                return;
             }
         }
 
@@ -171,6 +169,8 @@ pub fn run(
                 window.window().request_redraw();
             }
             Event::RedrawRequested(_) => {
+                // Only do a screen resize once per frame. This protects against
+                // spurious resize events that cause issues with the renderer.
                 if let Some(size) = new_size.take() {
                     viewer.handle_screen_resize(size);
                 }
@@ -200,8 +200,8 @@ pub fn run(
     });
 }
 
-fn input_event(
-    event: &Event<()>,
+fn input_event<T>(
+    event: &Event<T>,
     window: &Window,
     held_mouse_button: &Option<MouseButton>,
     previous_cursor: &mut Option<NormalizedScreenPosition>,
diff --git a/crates/fj-window/src/window.rs b/crates/fj-window/src/window.rs
index db1c57a84..25d709d39 100644
--- a/crates/fj-window/src/window.rs
+++ b/crates/fj-window/src/window.rs
@@ -8,7 +8,7 @@ pub struct Window(winit::window::Window);
 
 impl Window {
     /// Returns a new window with the given `EventLoop`.
-    pub fn new(event_loop: &EventLoop<()>) -> Result<Self, Error> {
+    pub fn new<T>(event_loop: &EventLoop<T>) -> Result<Self, Error> {
         let window = WindowBuilder::new()
             .with_title("Fornjot")
             .with_maximized(true)