(Edit: the problem occurs for all sound types, not only global sounds)
Steps to reproduce:
- Add a sound (default: local sound, manual trigger, not playing, looping, not muted).
- Save project
- Re-open project
Expected behavior: Playback position should still be at the start of the sound since it wasn't played yet.
Actual behavior: Playback position is set to an "invalid" position. The playback bar is clipping outside of its box.
After saving, before reopening the project:

After re-opening the project:

Notes:
- The problem also occurred with tat v0.5.5 (unfortunately I missed that paused sounds do not save their playback position correctly when I reported it working before).
- The problem is unrelated to the fact that the sound wasn't played before. It also occurs when the sound was played and then paused before saving and re-opening the project.
