diff --git a/include/engine/Module.hpp b/include/engine/Module.hpp
index df58f3fb..a848ffa6 100644
--- a/include/engine/Module.hpp
+++ b/include/engine/Module.hpp
@@ -84,6 +84,7 @@ struct Module {
 
 	template <class TParamQuantity = ParamQuantity>
 	void configParam(int paramId, float minValue, float maxValue, float defaultValue, std::string label = "", std::string unit = "", float displayBase = 0.f, float displayMultiplier = 1.f, float displayOffset = 0.f) {
+		assert(paramId < (int) params.size() && paramId < (int) paramQuantities.size());
 		if (paramQuantities[paramId])
 			delete paramQuantities[paramId];
 
diff --git a/src/app/Toolbar.cpp b/src/app/Toolbar.cpp
index e0379048..f8afd1e6 100644
--- a/src/app/Toolbar.cpp
+++ b/src/app/Toolbar.cpp
@@ -479,8 +479,6 @@ struct LogInItem : ui::MenuItem {
 
 
 struct ManageItem : ui::MenuItem {
-	ManageItem() {
-	}
 	void onAction(const event::Action &e) override {
 		std::thread t([&]() {
 			system::openBrowser("https://vcvrack.com/plugins.html");
diff --git a/src/engine/Module.cpp b/src/engine/Module.cpp
index da0f5648..3f51fdd2 100644
--- a/src/engine/Module.cpp
+++ b/src/engine/Module.cpp
@@ -16,6 +16,8 @@ Module::~Module() {
 }
 
 void Module::config(int numParams, int numInputs, int numOutputs, int numLights) {
+	// This method should only be called once.
+	assert(params.empty() && inputs.empty() && outputs.empty() && lights.empty() && paramQuantities.empty());
 	params.resize(numParams);
 	inputs.resize(numInputs);
 	outputs.resize(numOutputs);