AudioFileProcessor playback indicator not shown

[messmerd]

Bug Summary

Dragging and dropping samples into any preexisting AFP track causes the playback indicator in the AFP GUI to not display when notes are played. But if you drag and drop a sample into the Song Editor to create a new AFP track, the AFP playback indicator will display as expected. It also seems to work as expected when clicking the "Send to active instrument-track" context menu option for a sample from the Samples tab.

Steps to reproduce

1. Create AFP track via the Instrument tab
2. Drag and drop a sample from the Samples tab into the AFP GUI
3. Play a note - the AFP playback indicator will not be shown

Expected behavior

The playback indicator is shown in AFP when a note is played.

Actual behavior

It isn't.

Affected LMMS versions

master, stable 1.2.2, ...

[zonkmachine]

Confirmed. If you save and reload the project, the playback indicator will show up.