diff --git a/LEGO1/lego/legoomni/src/audio/mxbackgroundaudiomanager.cpp b/LEGO1/lego/legoomni/src/audio/mxbackgroundaudiomanager.cpp
index af7b904b..e8cd984d 100644
--- a/LEGO1/lego/legoomni/src/audio/mxbackgroundaudiomanager.cpp
+++ b/LEGO1/lego/legoomni/src/audio/mxbackgroundaudiomanager.cpp
@@ -230,6 +230,11 @@ void MxBackgroundAudioManager::StartAction(MxParam& p_param)
 	m_action2.SetObjectId(m_pendingPresenter->GetAction()->GetObjectId());
 	m_targetVolume = ((MxDSSound*) (m_pendingPresenter->GetAction()))->GetVolume();
 	m_pendingPresenter->SetVolume(0);
+
+	// Disabling the action here and starting it later once the actively presented music has been faded out.
+	// This was not necessary in retail because the streaming layer would implicitly not start another action
+	// before the previous one has ended (since it's all coming from JUKEBOX.SI), however since we now
+	// allow loading music from multiple SI files this would cause the new music to start immediately.
 	m_pendingPresenter->GetAction()->SetFlags(m_pendingPresenter->GetAction()->GetFlags() & ~MxDSAction::c_enabled);
 }
 
diff --git a/extensions/include/extensions/siloader.h b/extensions/include/extensions/siloader.h
index 652c25ee..ab3e69bc 100644
--- a/extensions/include/extensions/siloader.h
+++ b/extensions/include/extensions/siloader.h
@@ -4,10 +4,14 @@
 #include "legoworld.h"
 #include "mxatom.h"
 
-#include <interleaf.h>
 #include <map>
 #include <vector>
 
+namespace si
+{
+class Core;
+}
+
 namespace Extensions
 {
 class SiLoader {
diff --git a/extensions/src/siloader.cpp b/extensions/src/siloader.cpp
index f4be4a9d..aff434c4 100644
--- a/extensions/src/siloader.cpp
+++ b/extensions/src/siloader.cpp
@@ -5,6 +5,7 @@
 #include "mxstreamer.h"
 
 #include <SDL3/SDL.h>
+#include <interleaf.h>
 
 using namespace Extensions;