Reset the piano roll mode, the selection, and the undo/redo stacks

common/src/view.rs

@@ -187,6 +187,8 @@ impl View {
         self.dt = [0, dt];
         // Reset the notes.
         self.dn = self.initial_dn;
+        // Single track view.
+        self.single_track = true;
     }
 
     /// Returns the note delta.

io/src/lib.rs

@@ -282,15 +282,22 @@ impl IO {
         }
         // New file.
         if input.happened(&InputEvent::NewFile) {
+            // This prevents the previous file from being overwritten.
             paths_state.saves.filename = None;
             // Stop playing music.
             conn.on_new_file(state);
             // Reset the music.
             state.music = Music::default();
+            // Clear the selection.
+            state.select_mode = SelectMode::Single(None);
             // Reset the view.
             state.view.reset();
             // Reset the time.
             state.time.reset();
+            // Clear the undo/redo stacks.
+            self.undo.clear();
+            self.redo.clear();
+            state.unsaved_changes = false;
         }
         // Open file.
         else if input.happened(&InputEvent::OpenFile) {