Lmms: force mute when exporting tracks to avoid automation unmuting an instrument

[RiedleroD]

Bug Summary

When exporting tracks, all instruments except for the active one get muted. So far soo good. When I put a automation line that mutes and unmutes instruments to create a stutter effect, it gets activated by the automation line when another instrument is active. I found a workaround, which consists of the automation line muting a FX channel that is linked to the instrument.

Steps to reproduce

Open a project with several instruments, and create a automation line that mutes and unmutes an instrument. Then export tracks. Voliá there you go.

Expected behavior

The currently inactive instrument stays muted

Actual behavior

The currently inactive instrument gets unmuted

Screenshot

Affected LMMS versions

I tested it in Version 1.2.1 (Linux/x86_64, Qt 5.12.8, GCC 9.3.0), but I suspect all versions where 'export tracks' exists are affected.

[MvanSteenbergen]

I'd like to do this one!