deactivate "add key" button if nothing is selected

editor/src/plugins/animation/mod.rs

@@ -754,7 +754,7 @@ impl AnimationEditor {
 
             if let Ok(animation) = animations.try_get(selection.animation) {
                 self.track_list
-                    .sync_to_model(animation, graph, &selection, ui);
+                    .sync_to_model(editor_selection, animation, graph, &selection, ui);
 
                 let animation_tracks_data_state = animation.tracks_data().state();
                 let Some(animation_tracks_data) = animation_tracks_data_state.data_ref() else {

editor/src/plugins/animation/track.rs

@@ -1425,6 +1425,7 @@ impl TrackList {
 
     pub fn sync_to_model<G, N>(
         &mut self,
+        editor_selection: &Selection,
         animation: &Animation<Handle<N>>,
         graph: &G,
         selection: &AnimationSelection<N>,
@@ -1647,6 +1648,10 @@ impl TrackList {
             self.context_menu.set_target,
             WidgetMessage::Enabled(any_track_selected),
         );
+        ui.send_sync(
+            self.add_key,
+            WidgetMessage::Enabled(!editor_selection.is_empty()),
+        );
 
         for model_track in tracks_data.tracks() {
             let Some(model_track_binding) = animation.track_bindings().get(&model_track.id())