Use shared thumbnailcache for all plugin instances. Kind of a tricky thing with std::shared_ptr going on here using the deprecated unique method...But, oh well...

Source/PluginEditor.cpp

@@ -154,14 +154,21 @@ void PaulstretchpluginAudioProcessorEditor::chooseFile()
 	}
 }
 
-WaveformComponent::WaveformComponent(AudioFormatManager* afm) : m_thumbcache(100)
+std::shared_ptr<AudioThumbnailCache> g_thumbcache;
+
+WaveformComponent::WaveformComponent(AudioFormatManager* afm)
 {
+	if (g_thumbcache == nullptr)
+	{
+		g_thumbcache = std::make_shared<AudioThumbnailCache>(100);
+	}
+	m_thumbcache = g_thumbcache;
 	TimeSelectionChangedCallback = [](Range<double>, int) {};
 	if (m_use_opengl == true)
 		m_ogl.attachTo(*this);
 	// The default priority of 2 is a bit too low in some cases, it seems...
-	m_thumbcache.getTimeSliceThread().setPriority(3);
-	m_thumb = std::make_unique<AudioThumbnail>(512, *afm, m_thumbcache);
+	m_thumbcache->getTimeSliceThread().setPriority(3);
+	m_thumb = std::make_unique<AudioThumbnail>(512, *afm, *m_thumbcache);
 	m_thumb->addChangeListener(this);
 	setOpaque(true);
 }
@@ -271,7 +278,7 @@ void WaveformComponent::setAudioFile(File f)
 	{
 		m_waveimage = Image();
 		if (m_thumb != nullptr && f == m_curfile) // reloading same file, might happen that the overview needs to be redone...
-			m_thumbcache.removeThumb(m_thumb->getHashCode());
+			m_thumbcache->removeThumb(m_thumb->getHashCode());
 		if (m_thumb != nullptr)
 			m_thumb->reset(0, 0.0);
 		m_thumb->setSource(new FileInputSource(f));
@@ -430,3 +437,11 @@ int WaveformComponent::getTimeSelectionEdge(int x, int y)
 		return 2;
 	return 0;
 }
+
+void cleanUpGUI()
+{
+	if (g_thumbcache.unique())
+	{
+		g_thumbcache = nullptr;
+	}
+}

Source/PluginEditor.h

@@ -175,7 +175,7 @@ public:
 	Value ShowFileCacheRange;
 	void setRecordingPosition(double pos) { m_rec_pos = pos; }
 private:
-	AudioThumbnailCache m_thumbcache;
+	std::shared_ptr<AudioThumbnailCache> m_thumbcache;
 
 	std::unique_ptr<AudioThumbnail> m_thumb;
 	Range<double> m_view_range{ 0.0,1.0 };
@@ -221,3 +221,5 @@ private:
 	void chooseFile();
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (PaulstretchpluginAudioProcessorEditor)
 };
+
+void cleanUpGUI();

Source/PluginProcessor.cpp

@@ -96,6 +96,7 @@ PaulstretchpluginAudioProcessor::~PaulstretchpluginAudioProcessor()
 {
 	g_activeprocessors.erase(this);
 	m_bufferingthread.stopThread(1000);
+	cleanUpGUI();
 }
 
 void PaulstretchpluginAudioProcessor::setPreBufferAmount(int x)