diff --git a/source/backend/engine/CarlaEngineGraph.cpp b/source/backend/engine/CarlaEngineGraph.cpp
index d5be34a1e..d037fa362 100644
--- a/source/backend/engine/CarlaEngineGraph.cpp
+++ b/source/backend/engine/CarlaEngineGraph.cpp
@@ -1564,6 +1564,9 @@ void PatchbayGraph::removeAllPlugins()
 
 bool PatchbayGraph::connect(const uint groupA, const uint portA, const uint groupB, const uint portB) noexcept
 {
+    if (usingExternal)
+        return extGraph.connect(groupA, portA, groupB, portB);
+
     uint adjustedPortA = portA;
     uint adjustedPortB = portB;
 
@@ -1593,6 +1596,9 @@ bool PatchbayGraph::connect(const uint groupA, const uint portA, const uint grou
 
 bool PatchbayGraph::disconnect(const uint connectionId) noexcept
 {
+    if (usingExternal)
+        return extGraph.disconnect(connectionId);
+
     for (LinkedList<ConnectionToId>::Itenerator it=connections.list.begin(); it.valid(); it.next())
     {
         static const ConnectionToId fallback = { 0, 0, 0, 0, 0 };
@@ -1627,6 +1633,8 @@ bool PatchbayGraph::disconnect(const uint connectionId) noexcept
 
 void PatchbayGraph::disconnectGroup(const uint groupId) noexcept
 {
+    CARLA_SAFE_ASSERT(! usingExternal);
+
     for (LinkedList<ConnectionToId>::Itenerator it=connections.list.begin(); it.valid(); it.next())
     {
         static const ConnectionToId fallback = { 0, 0, 0, 0, 0 };
diff --git a/source/backend/engine/CarlaEngineRtAudio.cpp b/source/backend/engine/CarlaEngineRtAudio.cpp
index bdf000ef1..345c3dcf3 100644
--- a/source/backend/engine/CarlaEngineRtAudio.cpp
+++ b/source/backend/engine/CarlaEngineRtAudio.cpp
@@ -739,9 +739,18 @@ protected:
         CARLA_SAFE_ASSERT_RETURN(portName != nullptr && portName[0] != '\0', false);
         carla_debug("CarlaEngineRtAudio::connectRackMidiInPort(\"%s\")", portName);
 
-        RackGraph* const graph(pData->graph.getRackGraph());
-        CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
-        CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.ins.count() > 0, false);
+        if (pData->options.processMode == ENGINE_PROCESS_MODE_CONTINUOUS_RACK)
+        {
+            RackGraph* const graph(pData->graph.getRackGraph());
+            CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
+            CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.ins.count() > 0, false);
+        }
+        else
+        {
+            PatchbayGraph* const graph(pData->graph.getPatchbayGraph());
+            CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
+            CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.ins.count() > 0, false);
+        }
 
         CarlaString newRtMidiPortName;
         newRtMidiPortName += getName();
@@ -794,9 +803,18 @@ protected:
         CARLA_SAFE_ASSERT_RETURN(portName != nullptr && portName[0] != '\0', false);
         carla_debug("CarlaEngineRtAudio::connectRackMidiOutPort(\"%s\")", portName);
 
-        RackGraph* const graph(pData->graph.getRackGraph());
-        CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
-        CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.ins.count() > 0, false);
+        if (pData->options.processMode == ENGINE_PROCESS_MODE_CONTINUOUS_RACK)
+        {
+            RackGraph* const graph(pData->graph.getRackGraph());
+            CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
+            CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.outs.count() > 0, false);
+        }
+        else
+        {
+            PatchbayGraph* const graph(pData->graph.getPatchbayGraph());
+            CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
+            CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.outs.count() > 0, false);
+        }
 
         CarlaString newRtMidiPortName;
         newRtMidiPortName += getName();
@@ -849,9 +867,18 @@ protected:
         CARLA_SAFE_ASSERT_RETURN(portName != nullptr && portName[0] != '\0', false);
         carla_debug("CarlaEngineRtAudio::disconnectRackMidiInPort(\"%s\")", portName);
 
-        RackGraph* const graph(pData->graph.getRackGraph());
-        CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
-        CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.ins.count() > 0, false);
+        if (pData->options.processMode == ENGINE_PROCESS_MODE_CONTINUOUS_RACK)
+        {
+            RackGraph* const graph(pData->graph.getRackGraph());
+            CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
+            CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.ins.count() > 0, false);
+        }
+        else
+        {
+            PatchbayGraph* const graph(pData->graph.getPatchbayGraph());
+            CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
+            CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.ins.count() > 0, false);
+        }
 
         for (LinkedList<MidiInPort>::Itenerator it=fMidiIns.begin(); it.valid(); it.next())
         {
@@ -879,9 +906,18 @@ protected:
         CARLA_SAFE_ASSERT_RETURN(portName != nullptr && portName[0] != '\0', false);
         carla_debug("CarlaEngineRtAudio::disconnectRackMidiOutPort(\"%s\")", portName);
 
-        RackGraph* const graph(pData->graph.getRackGraph());
-        CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
-        CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.outs.count() > 0, false);
+        if (pData->options.processMode == ENGINE_PROCESS_MODE_CONTINUOUS_RACK)
+        {
+            RackGraph* const graph(pData->graph.getRackGraph());
+            CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
+            CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.outs.count() > 0, false);
+        }
+        else
+        {
+            PatchbayGraph* const graph(pData->graph.getPatchbayGraph());
+            CARLA_SAFE_ASSERT_RETURN(graph != nullptr, false);
+            CARLA_SAFE_ASSERT_RETURN(graph->extGraph.midiPorts.outs.count() > 0, false);
+        }
 
         const CarlaMutexLocker cml(fMidiOutMutex);