diff --git a/extras/AudioPluginHost/Source/Filters/FilterGraph.cpp b/extras/AudioPluginHost/Source/Filters/FilterGraph.cpp
index 395caf1661..b17a829d76 100644
--- a/extras/AudioPluginHost/Source/Filters/FilterGraph.cpp
+++ b/extras/AudioPluginHost/Source/Filters/FilterGraph.cpp
@@ -77,20 +77,6 @@ AudioProcessorGraph::Node::Ptr FilterGraph::getNodeForName (const String& name)
 
 void FilterGraph::addPlugin (const PluginDescription& desc, Point<double> p)
 {
-    struct AsyncCallback : public AudioPluginFormat::InstantiationCompletionCallback
-    {
-        AsyncCallback (FilterGraph& g, Point<double> pos)  : owner (g), position (pos)
-        {}
-
-        void completionCallback (AudioPluginInstance* instance, const String& error) override
-        {
-            owner.addFilterCallback (instance, error, position);
-        }
-
-        FilterGraph& owner;
-        Point<double> position;
-    };
-
     formatManager.createPluginInstanceAsync (desc,
                                              graph.getSampleRate(),
                                              graph.getBlockSize(),
diff --git a/extras/AudioPluginHost/Source/Filters/FilterGraph.h b/extras/AudioPluginHost/Source/Filters/FilterGraph.h
index bc0686a0fb..e2d2997de2 100644
--- a/extras/AudioPluginHost/Source/Filters/FilterGraph.h
+++ b/extras/AudioPluginHost/Source/Filters/FilterGraph.h
@@ -84,6 +84,23 @@ public:
     AudioProcessorGraph graph;
 
 private:
+    //==============================================================================
+    struct AsyncCallback : public AudioPluginFormat::InstantiationCompletionCallback
+    {
+        AsyncCallback(FilterGraph& g, Point<double> pos) : owner(g), position(pos)
+        {}
+
+        void completionCallback(AudioPluginInstance* instance, const String& error) override
+        {
+            owner.addFilterCallback(instance, error, position);
+        }
+
+        FilterGraph& owner;
+        Point<double> position;
+
+        JUCE_DECLARE_NON_COPYABLE (AsyncCallback)
+    };
+
     //==============================================================================
     AudioPluginFormatManager& formatManager;
     OwnedArray<PluginWindow> activePluginWindows;
diff --git a/extras/AudioPluginHost/Source/UI/GraphEditorPanel.cpp b/extras/AudioPluginHost/Source/UI/GraphEditorPanel.cpp
index c3b6036a31..e8d7d47378 100644
--- a/extras/AudioPluginHost/Source/UI/GraphEditorPanel.cpp
+++ b/extras/AudioPluginHost/Source/UI/GraphEditorPanel.cpp
@@ -1150,6 +1150,8 @@ struct GraphDocumentComponent::PluginListBoxModel    : public ListBoxModel,
    #if JUCE_IOS
     std::unique_ptr<AUScanner> scanner;
    #endif
+
+    JUCE_DECLARE_NON_COPYABLE (PluginListBoxModel)
 };
 
 //==============================================================================
diff --git a/extras/AudioPluginHost/Source/UI/PluginWindow.h b/extras/AudioPluginHost/Source/UI/PluginWindow.h
index 386ee07f83..5ae81109b6 100644
--- a/extras/AudioPluginHost/Source/UI/PluginWindow.h
+++ b/extras/AudioPluginHost/Source/UI/PluginWindow.h
@@ -111,8 +111,8 @@ private:
         list.scrollToEnsureRowIsOnscreen (log.size() - 1);
     }
 
-    constexpr static int maxLogSize = 300;
-    constexpr static int logSizeTrimThreshold = 400;
+    JUCE_CONSTEXPR static const int maxLogSize = 300;
+    JUCE_CONSTEXPR static const int logSizeTrimThreshold = 400;
 
     ListBox list { "Log", this };