Yes, that’s a bug, and I think that you’re the first person to report it.
Not really a “solution”, but a work-around. Hopefully the problem can be fixed in the next version so that a workaround isn’t necessary.
The problem occurs after the mouse crosses over into the label track while the mouse button is depressed. This causes focus to move from the audio track to the label track and somehow the new envelope point is then not being registered properly.
The problem can also be produced with a label track below the audio track, for example:
- Generate a tone.
- Add a label track.
- With the Envelope tool, grab the lower edge of the waveform and drag up tp create an envelop point at around -0.5 on the vertical scale.
- Repeat so that there are three envelope points spread out along the track.
- Grab the middle envelope point and drag down into the label track, then release the mouse button.
The envelope point is deleted as expected. - Try to add a new envelope point after the final envelope point.
Rather than creating a new envelope point at the position selected, the new envelope point is trapped on the left side of last envelope point.