diff --git a/include/engine/Module.hpp b/include/engine/Module.hpp
index e63c9a5e..06a15d36 100644
--- a/include/engine/Module.hpp
+++ b/include/engine/Module.hpp
@@ -286,8 +286,11 @@ struct Module {
 		onSampleRateChange();
 	}
 
-	struct ExpanderChangeEvent {};
-	/** Called after the Engine sample rate changes.
+	struct ExpanderChangeEvent {
+		/** False for left, true for right. */
+		bool side;
+	};
+	/** Called after an expander is added, removed, or changed on either the left or right side of the Module.
 	*/
 	virtual void onExpanderChange(const ExpanderChangeEvent& e) {}
 
diff --git a/src/app/RackWidget.cpp b/src/app/RackWidget.cpp
index e9850eb6..be53edb6 100644
--- a/src/app/RackWidget.cpp
+++ b/src/app/RackWidget.cpp
@@ -335,7 +335,7 @@ void RackWidget::pastePresetClipboardAction() {
 	}
 }
 
-static void RackWidget_updateAdjacent(RackWidget* that) {
+static void RackWidget_updateExpanders(RackWidget* that) {
 	for (widget::Widget* w : that->moduleContainer->children) {
 		math::Vec pLeft = w->box.pos.div(RACK_GRID_SIZE).round();
 		math::Vec pRight = w->box.getTopRight().div(RACK_GRID_SIZE).round();
@@ -375,7 +375,7 @@ void RackWidget::addModule(ModuleWidget* m) {
 	assert(m->box.size.y == RACK_GRID_HEIGHT);
 	moduleContainer->addChild(m);
 
-	RackWidget_updateAdjacent(this);
+	RackWidget_updateExpanders(this);
 }
 
 void RackWidget::addModuleAtMouse(ModuleWidget* mw) {
@@ -418,7 +418,7 @@ bool RackWidget::requestModulePos(ModuleWidget* mw, math::Vec pos) {
 
 	// Accept requested position
 	mw->setPosition(mwBox.pos);
-	RackWidget_updateAdjacent(this);
+	RackWidget_updateExpanders(this);
 	return true;
 }
 
@@ -520,7 +520,7 @@ void RackWidget::setModulePosForce(ModuleWidget* mw, math::Vec pos) {
 		xLimit = newPos.x + w->box.size.x;
 	}
 
-	RackWidget_updateAdjacent(this);
+	RackWidget_updateExpanders(this);
 }
 
 ModuleWidget* RackWidget::getModule(int64_t moduleId) {
diff --git a/src/engine/Engine.cpp b/src/engine/Engine.cpp
index 12bb1fdc..f2ee9c78 100644
--- a/src/engine/Engine.cpp
+++ b/src/engine/Engine.cpp
@@ -226,17 +226,27 @@ struct Engine::Internal {
 };
 
 
-static void Engine_updateExpander(Engine* that, Module::Expander* expander) {
-	if (expander->moduleId >= 0) {
-		if (!expander->module || expander->module->id != expander->moduleId) {
-			expander->module = that->getModule(expander->moduleId);
+static void Engine_updateExpander(Engine* that, Module* module, bool side) {
+	Module::Expander& expander = side ? module->rightExpander : module->leftExpander;
+	Module* oldExpanderModule = expander.module;
+
+	if (expander.moduleId >= 0) {
+		if (!expander.module || expander.module->id != expander.moduleId) {
+			expander.module = that->getModule(expander.moduleId);
 		}
 	}
 	else {
-		if (expander->module) {
-			expander->module = NULL;
+		if (expander.module) {
+			expander.module = NULL;
 		}
 	}
+
+	if (expander.module != oldExpanderModule) {
+		// Trigger ExpanderChangeEvent event
+		Module::ExpanderChangeEvent e;
+		e.side = side;
+		module->onExpanderChange(e);
+	}
 }
 
 
@@ -571,8 +581,8 @@ void Engine::step(int frames) {
 
 	// Update expander pointers
 	for (Module* module : internal->modules) {
-		Engine_updateExpander(this, &module->leftExpander);
-		Engine_updateExpander(this, &module->rightExpander);
+		Engine_updateExpander(this, module, false);
+		Engine_updateExpander(this, module, true);
 	}
 
 	// Launch workers
diff --git a/src/patch.cpp b/src/patch.cpp
index 8df2a684..c2693a3a 100644
--- a/src/patch.cpp
+++ b/src/patch.cpp
@@ -153,7 +153,8 @@ void PatchManager::saveTemplateDialog() {
 
 
 void PatchManager::saveAutosave() {
-	INFO("Saving autosave");
+	std::string patchPath = system::join(asset::autosavePath, "patch.json");
+	INFO("Saving autosave %s", patchPath.c_str());
 	json_t* rootJ = toJson();
 	if (!rootJ)
 		return;
@@ -161,7 +162,6 @@ void PatchManager::saveAutosave() {
 
 	// Write to temporary path and then rename it to the correct path
 	system::createDirectories(asset::autosavePath);
-	std::string patchPath = system::join(asset::autosavePath, "patch.json");
 	std::string tmpPath = patchPath + ".tmp";
 	FILE* file = std::fopen(tmpPath.c_str(), "w");
 	if (!file) {
@@ -265,8 +265,8 @@ void PatchManager::loadTemplateDialog() {
 
 
 void PatchManager::loadAutosave() {
-	INFO("Loading autosave");
 	std::string patchPath = system::join(asset::autosavePath, "patch.json");
+	INFO("Loading autosave %s", patchPath.c_str());
 	FILE* file = std::fopen(patchPath.c_str(), "r");
 	if (!file) {
 		// Exit silently