Envelope points disappear unexpectedly

[SteveDaulton]

Bug description

Envelope points will sometimes disappear unexpectedly without warning.

Steps to reproduce

1. Generate a 30 second tone.
2. Add envelope points at approximately: 5 seconds at 1.0, 20 seconds at 1.0, 12 seconds at 0.0.
3. Switch back to the Selection tool.
4. Split the track at about 2 seconds, 13 seconds, 25 seconds.
5. Double click on the 3rd clip to select it.
6. "Ctrl + D" to duplicate the clip onto a new track.
7. Single click on the new clip.
8. Drag the new clip a few seconds to the left.
9. Double click on the new clip.

Expected behavior

The new clip to be selected.

Actual behavior

The new clip is selected and the envelope disappears from the clip.

Audacity Version

current master / alpha / nightly build

Operating system

Linux

Additional context

No response