Of course, if you work with renoise some time you get used to this… but I think it would be real nice to think about a solution that, when you solo some track, you can have maybe like a different solo key that also temporarily makes the corresponding #Send device(s) act like ‘Mute Source’ so you can easily hear only the fxed track.
I have suggested similar to this before. I think I called it ‘isolate sends’, along with other soloing optionality.