Music Editor: Eraser tool doesn't take effect for the staff you put before

[Sheila111]

Describe the bug Music Editor: Eraser tool doesn't take effect for the staff you put before

Steps to reproduce the behavior

1. Navigate to https://arcade.makecode.com/beta#
2. Create a new project
3. Drag block play song until done
4. Click grey box to open music editor, create a new song and close music editor
5. Click grey box to open music editor again
6. Use eraser tool to erase any staff you put before

Actual behavior Eraser tool doesn't take effect for the staff you put before

Expect behavior Eraser tool can erase any staff you put before

Screenshot

Additional context 1.OS: Windows11 2.arcade version: 1.13.5 3.Microsoft MakeCode version: 8.6.4

[v-katherine]

This bug didn't reproduce when use 'Dog' in Music Editor.