Issue Summary

Pencil2D 0.6.6 nightly versions are crashing after deleting a sound layer

Expected Results

Moving or even touching the playhead shouldn't lead to the app crashing.

Steps to reproduce

1. File > Import > Sound > Create Layer > Load a sound file (format doesn't matter. I tested WAV & MP3's of different lengths)
2. Once loaded and the layer is created click on the playhead and be sure to move it at least one frame to the right (or any frames as long as it's been moved) Note: It seems even just clicking on the playhead on the first frame will allow the app to crash after the layer has been deleted but to be sure the event is registered move the playhead
3. Now delete the layer (doesn't matter if you use the buttons on the timeline or the delete layer action menu option)
4. It will crash 100%

System Information

Nightly Build Aug 12 2021

commit: d2d8907
date: 2021-08-12_16:58:31

Operating System: Windows 10 Version 2009
CPU Architecture: x86_64
Qt Version: 5.15.2