diff --git a/crates/tek_sequencer/src/arranger_main.rs b/crates/tek_sequencer/src/arranger_main.rs
index 3dff0276..dee5272f 100644
--- a/crates/tek_sequencer/src/arranger_main.rs
+++ b/crates/tek_sequencer/src/arranger_main.rs
@@ -7,9 +7,9 @@ pub fn main () -> Usually<()> {
     Ok(())
 }
 
-struct ArrangerStandalone {
+struct ArrangerStandalone<E: Engine> {
     /// Contains all the sequencers.
-    arranger:        Arranger,
+    arranger:        Arranger<E>,
     /// Controls the JACK transport.
     transport:       Option<TransportToolbar>,
     /// This allows the sequencer view to be moved or hidden.
@@ -18,8 +18,6 @@ struct ArrangerStandalone {
     focus:           usize,
 }
 
-focus!(ArrangerStandalone (focus) : 2 => [ transport, arranger ]);
-
 #[derive(Debug, Parser)]
 #[command(version, about, long_about = None)]
 pub struct ArrangerCli {
@@ -40,7 +38,7 @@ pub struct ArrangerCli {
     scenes: usize,
 }
 
-impl ArrangerStandalone {
+impl<E: Engine> ArrangerStandalone<E> {
     pub fn from_args () -> Usually<Self> {
         let args = ArrangerCli::parse();
         let mut arranger = Arranger::new("");
@@ -75,7 +73,7 @@ impl ArrangerStandalone {
     }
 }
 
-impl Render<Tui> for ArrangerStandalone {
+impl Render<Tui> for ArrangerStandalone<Tui> {
     fn render (&self, to: &mut Tui) -> Perhaps<Rect> {
         let area = to.area();
         let sequencer = self.arranger.sequencer();
@@ -94,55 +92,73 @@ impl Render<Tui> for ArrangerStandalone {
     }
 }
 
-impl Handle<Tui> for ArrangerStandalone {
-    fn handle (&mut self, e: &AppEvent) -> Usually<bool> {
-        match e {
-            AppEvent::Input(Event::Key(KeyEvent { code: KeyCode::Char(' '), .. })) => {
+impl Handle<Tui> for ArrangerStandalone<Tui> {
+    fn handle (&mut self, from: &Tui) -> Perhaps<bool> {
+        match from.event() {
+            key!(KeyCode::Char(' ')) => {
                 if let Some(ref mut transport) = self.transport {
                     transport.toggle_play()?;
-                    Ok(true)
+                    Ok(Some(true))
                 } else {
-                    Ok(false)
+                    Ok(None)
                 }
             },
-            AppEvent::Input(Event::Key(KeyEvent { code: KeyCode::Tab, .. })) => {
-                self.focus_next();
-                Ok(true)
+            key!(KeyCode::Tab) => {
+                self.arranger.focus_next();
+                Ok(Some(true))
             },
-            AppEvent::Input(Event::Key(KeyEvent { code: KeyCode::BackTab, .. })) => {
-                self.focus_prev();
-                Ok(true)
+            key!(KeyCode::BackTab) => {
+                self.arranger.focus_prev();
+                Ok(Some(true))
             },
-            AppEvent::Input(Event::Key(KeyEvent { code: KeyCode::Down, .. })) => {
+            key!(KeyCode::Down) => {
                 if self.focus == 0 || (
                     self.focus == 1 && self.arranger.is_last_row()
                 ) {
-                    self.focus_next();
-                    Ok(true)
+                    self.arranger.focus_next();
+                    Ok(Some(true))
                 } else {
-                    self.focused_mut().handle(e)
+                    self.arranger.focused_mut().handle(from)
                 }
             },
-            AppEvent::Input(Event::Key(KeyEvent { code: KeyCode::Up, .. })) => {
+            key!(KeyCode::Up) => {
                 if self.focus == 1 && self.arranger.is_first_row() {
-                    self.focus_prev();
-                    Ok(true)
+                    self.arranger.focus_prev();
+                    Ok(Some(true))
                 } else {
-                    self.focused_mut().handle(e)
+                    self.arranger.focused_mut().handle(from)
                 }
             },
-            _ => self.focused_mut().handle(e)
+            _ => self.arranger.focused_mut().handle(from)
         }
     }
 }
 
-struct SequencerProxy(Arc<RwLock<Arranger>>);
+struct SequencerProxy<E: Engine>(Arc<RwLock<Arranger<E>>>);
 
-impl Handle for SequencerProxy {
-    fn handle (&mut self, e: &AppEvent) -> Usually<bool> {
-        match self.0.write().unwrap().sequencer_mut() {
-            Some(sequencer) => sequencer.handle(e),
-            None => Ok(false)
-        }
+impl Handle<Tui> for SequencerProxy<Tui> {
+    fn handle (&mut self, from: &Tui) -> Perhaps<bool> {
+        self.0.write().unwrap().handle(from)
+    }
+}
+
+impl Focus<2, E: Engine> for ArrangerStandalone<E> {
+    fn focus (&self) -> usize {
+        self.focus
+    }
+    fn focus_mut (&mut self) -> &mut usize {
+        &mut self.focus
+    }
+    fn focusable (&self) -> [&dyn Focusable<E>;2] {
+        [
+            &self.transport as &dyn Focusable<E>,
+            &self.arranger  as &dyn Focusable<E>,
+        ]
+    }
+    fn focusable_mut (&mut self) -> [&mut dyn Focusable<E>;2] {
+        [
+            &mut self.transport as &mut dyn Focusable<E>,
+            &mut self.arranger  as &mut dyn Focusable<E>,
+        ]
     }
 }