diff --git a/config/keys_clock.edn b/config/keys_clock.edn
index 5a0763be..3f707559 100644
--- a/config/keys_clock.edn
+++ b/config/keys_clock.edn
@@ -1,2 +1,2 @@
-(@space       clock toggle)
-(@shift-space clock toggle 0)
+(@space       clock toggle-playback 0)
+(@shift-space clock toggle-playback 0)
diff --git a/crates/app/src/lib.rs b/crates/app/src/lib.rs
index cda6e94b..f1d59d7f 100644
--- a/crates/app/src/lib.rs
+++ b/crates/app/src/lib.rs
@@ -42,33 +42,29 @@ mod config; pub use self::config::*;
 mod model;  pub use self::model::*;
 mod view;   pub use self::view::*;
 
-#[cfg(test)] #[test] fn test_model () {
+#[cfg(test)] #[test] fn test_model () -> Usually<()> {
     let mut app = App::default();
     let _ = app.clip();
     let _ = app.toggle_loop();
-}
-
-#[cfg(test)] #[test] fn test_model_scene () {
-    let mut app = App::default();
+    //let _ = app.tracks_add(8, None, &[], &[])?;
+    //let _ = app.track_add_focus()?;
     let _ = app.scene_longest();
     let _ = app.scene();
     let _ = app.scene_mut();
-    let _ = app.scene_add(None, None);
-    app.scene_del(0);
+    let _ = app.scene_add(None, None)?;
+    let _ = app.scene_add_focus()?;
+    let scene = app.scene_del(0);
     let scene = Scene::default();
     let _ = scene.pulses();
     let _ = scene.is_playing(&[]);
-}
-
-#[cfg(test)] #[test] fn test_view_clock () {
-    let _ = button_play_pause(true);
-    let mut app = App::default();
     let _ = app.view_transport();
     let _ = app.view_status();
     let _ = app.update_clock();
+    Ok(())
 }
 
 #[cfg(test)] #[test] fn test_view_layout () {
+    let _ = button_play_pause(true);
     let _ = button_2("", "", true);
     let _ = button_2("", "", false);
     let _ = button_3("", "", "", true);
diff --git a/crates/app/src/model/scene.rs b/crates/app/src/model/scene.rs
index 5159eeb0..353133ac 100644
--- a/crates/app/src/model/scene.rs
+++ b/crates/app/src/model/scene.rs
@@ -46,13 +46,16 @@ pub trait HasScenes: HasSelection + HasEditor + Send + Sync {
         self.scenes().iter().map(|s|s.name.len()).fold(0, usize::max)
     }
     fn scene (&self) -> Option<&Scene> {
-        self.selected().scene().and_then(|s|self.scenes().get(s))
+        self.selected().scene()
+            .and_then(|s|self.scenes().get(s))
     }
     fn scene_mut (&mut self) -> Option<&mut Scene> {
-        self.selected().scene().and_then(|s|self.scenes_mut().get_mut(s))
+        self.selected().scene()
+            .and_then(|s|self.scenes_mut().get_mut(s))
     }
-    fn scene_del (&mut self, index: usize) {
-        self.selected().scene().and_then(|s|Some(self.scenes_mut().remove(index)));
+    fn scene_del (&mut self, index: usize) -> Option<Scene> {
+        self.selected().scene()
+            .and_then(|s|Some(self.scenes_mut().remove(index)))
     }
     /// Set the color of a scene, returning the previous one.
     fn scene_set_color (&mut self, index: usize, color: ItemTheme) -> ItemTheme {
diff --git a/crates/device/src/clock/clock_api.rs b/crates/device/src/clock/clock_api.rs
index e9161ec4..e8544525 100644
--- a/crates/device/src/clock/clock_api.rs
+++ b/crates/device/src/clock/clock_api.rs
@@ -29,11 +29,11 @@ impl ClockCommand {
         state.pause_at(position)?;
         Ok(None)
     }
-    fn toggle_playback (state: &mut Clock, position: Option<u32>) -> Perhaps<Self> {
+    fn toggle_playback (state: &mut Clock, position: u32) -> Perhaps<Self> {
         if state.is_rolling() {
-            state.pause_at(position)?;
+            state.pause_at(Some(position))?;
         } else {
-            state.play_from(position)?;
+            state.play_from(Some(position))?;
         }
         Ok(None)
     }
diff --git a/deps/tengri b/deps/tengri
index 20ccff13..cb8fd269 160000
--- a/deps/tengri
+++ b/deps/tengri
@@ -1 +1 @@
-Subproject commit 20ccff13de1957c1268c6fec64048d8ae1767fd5
+Subproject commit cb8fd26922fd1cfad4ceadeb89e48544531a178e