From 6c0cf6832e351f8800f3371a7f64f0a101625623 Mon Sep 17 00:00:00 2001
From: vsariola <5684185+vsariola@users.noreply.github.com>
Date: Sat, 6 Feb 2021 19:15:06 +0200
Subject: [PATCH] fix(tracker): clamp CurrentUnit to valid values when
 instrument changes

---
 tracker/instruments.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tracker/instruments.go b/tracker/instruments.go
index c8e5885..b4f0fa5 100644
--- a/tracker/instruments.go
+++ b/tracker/instruments.go
@@ -112,6 +112,9 @@ func (t *Tracker) layoutInstrumentNames(gtx C) D {
 	dims := instrumentList.Layout(gtx)
 	if t.CurrentInstrument != t.InstrumentDragList.SelectedItem {
 		t.CurrentInstrument = t.InstrumentDragList.SelectedItem
+		if l := len(t.song.Patch.Instruments[t.CurrentInstrument].Units); t.CurrentUnit >= l {
+			t.CurrentUnit = l - 1
+		}
 		op.InvalidateOp{}.Add(gtx.Ops)
 	}
 	return dims