diff --git a/src/engine/engine.h b/src/engine/engine.h
index 264349447..5594ad359 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -577,7 +577,7 @@ class DivEngine {
   DivWorkPool* renderPool;
 
   // MIDI stuff
-  std::function<int(const TAMidiMessage&)> midiCallback=[](const TAMidiMessage&) -> int {return -2;};
+  std::function<int(const TAMidiMessage&)> midiCallback=[](const TAMidiMessage&) -> int {return -3;};
 
   void processRowPre(int i);
   void processRow(int i, bool afterDelay);
@@ -1338,7 +1338,7 @@ class DivEngine {
     void setMidiVolExp(float value);
 
     // set MIDI input callback
-    // if the specified function returns -2, note feedback will be inhibited.
+    // if the specified function returns -3, note feedback will be inhibited.
     void setMidiCallback(std::function<int(const TAMidiMessage&)> what);
 
     // send MIDI message
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 4378de719..183b0a7b6 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -2252,7 +2252,7 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
       }
     }
     int ins=-1;
-    if ((ins=midiCallback(msg))!=-2) {
+    if ((ins=midiCallback(msg))!=-3) {
       int chan=msg.type&15;
       switch (msg.type&0xf0) {
         case TA_MIDI_NOTE_OFF: {
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index fa0f7d543..bedc96c18 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -7905,7 +7905,7 @@ bool FurnaceGUI::init() {
   userEvents=SDL_RegisterEvents(1);
 
   e->setMidiCallback([this](const TAMidiMessage& msg) -> int {
-    if (introPos<11.0) return -2;
+    if (introPos<11.0) return -3;
     midiLock.lock();
     midiQueue.push(msg);
     if (userEvents!=0xffffffff && midiWakeUp) {
@@ -7918,11 +7918,11 @@ bool FurnaceGUI::init() {
     }
     midiLock.unlock();
     e->setMidiBaseChan(cursor.xCoarse);
-    if (msg.type==TA_MIDI_SYSEX) return -2;
-    if (midiMap.valueInputStyle!=0 && cursor.xFine!=0 && edit) return -2;
-    if (!midiMap.noteInput) return -2;
-    if (learning!=-1) return -2;
-    if (midiMap.at(msg)) return -2;
+    if (msg.type==TA_MIDI_SYSEX) return -3;
+    if (midiMap.valueInputStyle!=0 && cursor.xFine!=0 && edit) return -3;
+    if (!midiMap.noteInput) return -3;
+    if (learning!=-1) return -3;
+    if (midiMap.at(msg)) return -3;
 
     if (curWindowThreadSafe==GUI_WINDOW_WAVE_EDIT || curWindowThreadSafe==GUI_WINDOW_WAVE_LIST) {
       if ((msg.type&0xf0)==TA_MIDI_NOTE_ON) {
@@ -7933,7 +7933,7 @@ bool FurnaceGUI::init() {
           e->stopWavePreviewNoLock();
         }
       }
-      return -2;
+      return -3;
     }
 
     if (curWindowThreadSafe==GUI_WINDOW_SAMPLE_EDIT || curWindowThreadSafe==GUI_WINDOW_SAMPLE_LIST) {
@@ -7945,7 +7945,7 @@ bool FurnaceGUI::init() {
           e->stopSamplePreviewNoLock();
         }
       }
-      return -2;
+      return -3;
     }
 
     if (midiMap.directChannel && midiMap.directProgram) return -1;