diff --git a/include/AudioEngine.h b/include/AudioEngine.h
index d0f269d87..dec8f2592 100644
--- a/include/AudioEngine.h
+++ b/include/AudioEngine.h
@@ -32,10 +32,10 @@
 #endif
 
 #include <QThread>
-#include <QVector>
 #include <QWaitCondition>
 #include <samplerate.h>
 
+#include <vector>
 
 #include "lmms_basics.h"
 #include "LocklessList.h"
@@ -416,7 +416,7 @@ private:
 
 	bool m_renderOnly;
 
-	QVector<AudioPort *> m_audioPorts;
+	std::vector<AudioPort *> m_audioPorts;
 
 	fpp_t m_framesPerPeriod;
 
@@ -430,7 +430,7 @@ private:
 	surroundSampleFrame * m_outputBufferWrite;
 
 	// worker thread stuff
-	QVector<AudioEngineWorkerThread *> m_workers;
+	std::vector<AudioEngineWorkerThread *> m_workers;
 	int m_numWorkers;
 
 	// playhandle stuff
diff --git a/include/AudioEngineWorkerThread.h b/include/AudioEngineWorkerThread.h
index 112930808..16de6ff6f 100644
--- a/include/AudioEngineWorkerThread.h
+++ b/include/AudioEngineWorkerThread.h
@@ -100,9 +100,9 @@ public:
 							JobQueue::OperationMode _opMode = JobQueue::Static )
 	{
 		resetJobQueue( _opMode );
-		for( typename T::ConstIterator it = _vec.begin(); it != _vec.end(); ++it )
+		for (const auto& job : _vec)
 		{
-			addJob( *it );
+			addJob(job);
 		}
 	}
 
diff --git a/include/AudioJack.h b/include/AudioJack.h
index 2ef0f665c..164258e5f 100644
--- a/include/AudioJack.h
+++ b/include/AudioJack.h
@@ -35,7 +35,7 @@
 #endif
 
 #include <atomic>
-#include <QVector>
+#include <vector>
 
 #include "AudioDevice.h"
 #include "AudioDeviceSetupWidget.h"
@@ -117,7 +117,7 @@ private:
 	std::atomic<bool> m_stopped;
 
 	std::atomic<MidiJack *> m_midiClient;
-	QVector<jack_port_t *> m_outputPorts;
+	std::vector<jack_port_t *> m_outputPorts;
 	jack_default_audio_sample_t * * m_tempOutBufs;
 	surroundSampleFrame * m_outBuf;
 
diff --git a/include/AutomatableModel.h b/include/AutomatableModel.h
index 1e6d5eda3..2b93a514c 100644
--- a/include/AutomatableModel.h
+++ b/include/AutomatableModel.h
@@ -78,7 +78,7 @@ class LMMS_EXPORT AutomatableModel : public Model, public JournallingObject
 	Q_OBJECT
 	MM_OPERATORS
 public:
-	using AutoModelVector = QVector<AutomatableModel*>;
+	using AutoModelVector = std::vector<AutomatableModel*>;
 
 	enum ScaleType
 	{
diff --git a/include/AutomationClip.h b/include/AutomationClip.h
index 10c714c3d..fc6a26d0e 100644
--- a/include/AutomationClip.h
+++ b/include/AutomationClip.h
@@ -62,7 +62,7 @@ public:
 	} ;
 
 	using timeMap = QMap<int, AutomationNode>;
-	using objectVector = QVector<QPointer<AutomatableModel>>;
+	using objectVector = std::vector<QPointer<AutomatableModel>>;
 
 	using TimemapIterator = timeMap::const_iterator;
 
@@ -167,7 +167,7 @@ public:
 
 
 	static bool isAutomated( const AutomatableModel * _m );
-	static QVector<AutomationClip *> clipsForModel( const AutomatableModel * _m );
+	static std::vector<AutomationClip*> clipsForModel(const AutomatableModel* _m);
 	static AutomationClip * globalAutomationClip( AutomatableModel * _m );
 	static void resolveAllIDs();
 
@@ -190,6 +190,15 @@ private:
 	void generateTangents(timeMap::iterator it, int numToGenerate);
 	float valueAt( timeMap::const_iterator v, int offset ) const;
 
+	/**
+	 * @brief
+	 * This function combines the song tracks, pattern store tracks,
+	 * and the global automation track all in one vector.
+	 *
+	 * @return std::vector<Track*>
+	 */
+	static std::vector<Track*> combineAllTracks();
+
 	// Mutex to make methods involving automation clips thread safe
 	// Mutable so we can lock it from const objects
 #if (QT_VERSION >= QT_VERSION_CHECK(5,14,0))
@@ -199,7 +208,7 @@ private:
 #endif
 
 	AutomationTrack * m_autoTrack;
-	QVector<jo_id_t> m_idsToResolve;
+	std::vector<jo_id_t> m_idsToResolve;
 	objectVector m_objects;
 	timeMap m_timeMap;	// actual values
 	timeMap m_oldTimeMap;	// old values for storing the values before setDragValue() is called.
diff --git a/include/AutomationEditor.h b/include/AutomationEditor.h
index c2ab98092..a1c4d694f 100644
--- a/include/AutomationEditor.h
+++ b/include/AutomationEditor.h
@@ -27,6 +27,7 @@
 #define LMMS_GUI_AUTOMATION_EDITOR_H
 
 #include <QWidget>
+#include <array>
 
 #include "Editor.h"
 
@@ -180,7 +181,7 @@ private:
 	ComboBoxModel m_zoomingYModel;
 	ComboBoxModel m_quantizeModel;
 
-	static const QVector<float> m_zoomXLevels;
+	static const std::array<float, 7> m_zoomXLevels;
 
 	FloatModel * m_tensionModel;
 
diff --git a/include/ConfigManager.h b/include/ConfigManager.h
index eee069681..f6239c297 100644
--- a/include/ConfigManager.h
+++ b/include/ConfigManager.h
@@ -30,9 +30,9 @@
 #include <QMap>
 #include <QPair>
 #include <QStringList>
-#include <QVector>
 #include <QObject>
 
+#include <vector>
 #include "lmms_export.h"
 
 
@@ -239,11 +239,8 @@ public:
 
 	void addRecentlyOpenedProject(const QString & _file);
 
-	const QString & value(const QString & cls,
-					const QString & attribute) const;
-	const QString & value(const QString & cls,
-					const QString & attribute,
-					const QString & defaultVal) const;
+	QString value(const QString& cls, const QString& attribute, const QString& defaultVal = "") const;
+
 	void setValue(const QString & cls, const QString & attribute,
 						const QString & value);
 	void deleteValue(const QString & cls, const QString & attribute);
@@ -302,7 +299,7 @@ private:
 	unsigned int m_configVersion;
 	QStringList m_recentlyOpenedProjects;
 
-	using stringPairVector = QVector<QPair<QString, QString>>;
+	using stringPairVector = std::vector<QPair<QString, QString>>;
 	using settingsMap = QMap<QString, stringPairVector>;
 	settingsMap m_settings;
 
diff --git a/include/Controller.h b/include/Controller.h
index 0a5eb0f36..b176b1f74 100644
--- a/include/Controller.h
+++ b/include/Controller.h
@@ -45,7 +45,7 @@ class ControllerDialog;
 
 } // namespace gui
 
-using ControllerVector = QVector<Controller*>;
+using ControllerVector = std::vector<Controller*>;
 
 class LMMS_EXPORT Controller : public Model, public JournallingObject
 {
diff --git a/include/ControllerConnection.h b/include/ControllerConnection.h
index 4473b68e0..b60687123 100644
--- a/include/ControllerConnection.h
+++ b/include/ControllerConnection.h
@@ -30,12 +30,13 @@
 #define LMMS_CONTROLLER_CONNECTION_H
 
 #include <QObject>
-#include <QVector>
 
 #include "Controller.h"
 #include "JournallingObject.h"
 #include "ValueBuffer.h"
 
+#include <vector>
+
 namespace lmms
 {
 
@@ -46,7 +47,7 @@ namespace gui
 class ControllerConnectionDialog;
 }
 
-using ControllerConnectionVector = QVector<ControllerConnection*>;
+using ControllerConnectionVector = std::vector<ControllerConnection*>;
 
 class LMMS_EXPORT ControllerConnection : public QObject, public JournallingObject
 {
diff --git a/include/EffectChain.h b/include/EffectChain.h
index 57cf8d547..f9482174e 100644
--- a/include/EffectChain.h
+++ b/include/EffectChain.h
@@ -69,7 +69,7 @@ public:
 
 
 private:
-	using EffectList = QVector<Effect*>;
+	using EffectList = std::vector<Effect*>;
 	EffectList m_effects;
 
 	BoolModel m_enabledModel;
diff --git a/include/EnvelopeAndLfoParameters.h b/include/EnvelopeAndLfoParameters.h
index a713a90f3..02abd07e3 100644
--- a/include/EnvelopeAndLfoParameters.h
+++ b/include/EnvelopeAndLfoParameters.h
@@ -25,7 +25,7 @@
 #ifndef LMMS_ENVELOPE_AND_LFO_PARAMETERS_H
 #define LMMS_ENVELOPE_AND_LFO_PARAMETERS_H
 
-#include <QVector>
+#include <vector>
 
 #include "JournallingObject.h"
 #include "AutomatableModel.h"
diff --git a/include/InstrumentFunctions.h b/include/InstrumentFunctions.h
index f62b74e9a..61d625d83 100644
--- a/include/InstrumentFunctions.h
+++ b/include/InstrumentFunctions.h
@@ -119,7 +119,7 @@ public:
 	};
 
 
-	struct ChordTable : public QVector<Chord>
+	struct ChordTable
 	{
 	private:
 		ChordTable();
@@ -131,6 +131,7 @@ public:
 		};
 
 		static std::array<Init, NUM_CHORD_TABLES> s_initTable;
+		std::vector<Chord> m_chords;
 
 	public:
 		static const ChordTable & getInstance()
@@ -150,6 +151,11 @@ public:
 		{
 			return getByName( name, false );
 		}
+
+		const std::vector<Chord>& chords() const
+		{
+			return m_chords;
+		}
 	};
 
 
diff --git a/include/MidiClient.h b/include/MidiClient.h
index 3a64f709c..1eb04402b 100644
--- a/include/MidiClient.h
+++ b/include/MidiClient.h
@@ -26,7 +26,7 @@
 #define LMMS_MIDI_CLIENT_H
 
 #include <QStringList>
-#include <QVector>
+#include <vector>
 
 
 #include "MidiEvent.h"
@@ -111,7 +111,7 @@ public:
 	static MidiClient * openMidiClient();
 
 protected:
-	QVector<MidiPort *> m_midiPorts;
+	std::vector<MidiPort *> m_midiPorts;
 
 } ;
 
diff --git a/include/Mixer.h b/include/Mixer.h
index 6589836c4..35787a414 100644
--- a/include/Mixer.h
+++ b/include/Mixer.h
@@ -39,7 +39,7 @@ namespace lmms
 
 
 class MixerRoute;
-using MixerRouteVector = QVector<MixerRoute*>;
+using MixerRouteVector = std::vector<MixerRoute*>;
 
 class MixerChannel : public ThreadableJob
 {
@@ -219,7 +219,7 @@ public:
 
 private:
 	// the mixer channels in the mixer. index 0 is always master.
-	QVector<MixerChannel *> m_mixerChannels;
+	std::vector<MixerChannel*> m_mixerChannels;
 
 	// make sure we have at least num channels
 	void allocateChannelsTo(int num);
diff --git a/include/Note.h b/include/Note.h
index 15aeaa2ce..dd261b3af 100644
--- a/include/Note.h
+++ b/include/Note.h
@@ -27,7 +27,7 @@
 #define LMMS_NOTE_H
 
 #include <optional>
-#include <QVector>
+#include <vector>
 
 #include "volume.h"
 #include "panning.h"
@@ -249,7 +249,7 @@ private:
 	DetuningHelper * m_detuning;
 };
 
-using NoteVector = QVector<Note*>;
+using NoteVector = std::vector<Note*>;
 
 struct NoteBounds
 {
diff --git a/include/PeakController.h b/include/PeakController.h
index 357e2a95d..de9da3b1c 100644
--- a/include/PeakController.h
+++ b/include/PeakController.h
@@ -36,7 +36,7 @@ namespace lmms
 
 class PeakControllerEffect;
 
-using PeakControllerEffectVector = QVector<PeakControllerEffect*>;
+using PeakControllerEffectVector = std::vector<PeakControllerEffect*>;
 
 class LMMS_EXPORT PeakController : public Controller
 {
diff --git a/include/PianoRoll.h b/include/PianoRoll.h
index 6100792d5..03b93d816 100644
--- a/include/PianoRoll.h
+++ b/include/PianoRoll.h
@@ -27,9 +27,10 @@
 #ifndef LMMS_GUI_PIANO_ROLL_H
 #define LMMS_GUI_PIANO_ROLL_H
 
-#include <QVector>
 #include <QWidget>
 
+#include <vector>
+
 #include "Editor.h"
 #include "ComboBoxModel.h"
 #include "SerializingObject.h"
@@ -291,7 +292,7 @@ private:
 
 	PositionLine * m_positionLine;
 
-	QVector<QString> m_nemStr; // gui names of each edit mode
+	std::vector<QString> m_nemStr; // gui names of each edit mode
 	QMenu * m_noteEditMenu; // when you right click below the key area
 
 	QList<int> m_markedSemiTones;
@@ -358,8 +359,8 @@ private:
 	ComboBoxModel m_chordModel;
 	ComboBoxModel m_snapModel;
 
-	static const QVector<float> m_zoomLevels;
-	static const QVector<float> m_zoomYLevels;
+	static const std::vector<float> m_zoomLevels;
+	static const std::vector<float> m_zoomYLevels;
 
 	MidiClip* m_midiClip;
 	NoteVector m_ghostNotes;
diff --git a/include/PluginFactory.h b/include/PluginFactory.h
index 001ea190a..10c76e4ee 100644
--- a/include/PluginFactory.h
+++ b/include/PluginFactory.h
@@ -27,12 +27,12 @@
 
 #include <memory>
 #include <string>
+#include <vector>
 
 #include <QFileInfo>
 #include <QHash>
 #include <QList>
 #include <QString>
-#include <QVector>
 
 #include "lmms_export.h"
 #include "Plugin.h"
@@ -99,7 +99,7 @@ private:
 	PluginInfoList m_pluginInfos;
 
 	QMap<QString, PluginInfoAndKey> m_pluginByExt;
-	QVector<std::string> m_garbage; //!< cleaned up at destruction
+	std::vector<std::string> m_garbage; //!< cleaned up at destruction
 
 	QHash<QString, QString> m_errors;
 
diff --git a/include/RenderManager.h b/include/RenderManager.h
index 5240e96a8..43f696f14 100644
--- a/include/RenderManager.h
+++ b/include/RenderManager.h
@@ -78,8 +78,8 @@ private:
 
 	std::unique_ptr<ProjectRenderer> m_activeRenderer;
 
-	QVector<Track*> m_tracksToRender;
-	QVector<Track*> m_unmuted;
+	std::vector<Track*> m_tracksToRender;
+	std::vector<Track*> m_unmuted;
 } ;
 
 
diff --git a/include/StepRecorder.h b/include/StepRecorder.h
index 456e69a69..55435617c 100644
--- a/include/StepRecorder.h
+++ b/include/StepRecorder.h
@@ -59,7 +59,7 @@ class StepRecorder : public QObject
 	void setCurrentMidiClip(MidiClip* newMidiClip);
 	void setStepsLength(const TimePos& newLength);
 
-	QVector<Note*> getCurStepNotes();
+	std::vector<Note*> getCurStepNotes();
 
 	bool isRecording() const
 	{
@@ -142,7 +142,7 @@ class StepRecorder : public QObject
 		QElapsedTimer releasedTimer;
 	} ;
 
-	QVector<StepNote*> m_curStepNotes; // contains the current recorded step notes (i.e. while user still press the notes; before they are applied to the clip)
+	std::vector<StepNote*> m_curStepNotes; // contains the current recorded step notes (i.e. while user still press the notes; before they are applied to the clip)
 
 	StepNote* findCurStepNote(const int key);
 
diff --git a/include/Track.h b/include/Track.h
index ff3c1ae00..000d564f7 100644
--- a/include/Track.h
+++ b/include/Track.h
@@ -25,7 +25,8 @@
 #ifndef LMMS_TRACK_H
 #define LMMS_TRACK_H
 
-#include <QVector>
+#include <vector>
+
 #include <QColor>
 
 #include "AutomatableModel.h"
@@ -69,7 +70,7 @@ class LMMS_EXPORT Track : public Model, public JournallingObject
 	mapPropertyFromModel(bool,isMuted,setMuted,m_mutedModel);
 	mapPropertyFromModel(bool,isSolo,setSolo,m_soloModel);
 public:
-	using clipVector = QVector<Clip*>;
+	using clipVector = std::vector<Clip*>;
 
 	enum TrackTypes
 	{
diff --git a/include/TrackContainer.h b/include/TrackContainer.h
index f99273ba2..8739a9e9f 100644
--- a/include/TrackContainer.h
+++ b/include/TrackContainer.h
@@ -49,7 +49,7 @@ class LMMS_EXPORT TrackContainer : public Model, public JournallingObject
 {
 	Q_OBJECT
 public:
-	using TrackList = QVector<Track*>;
+	using TrackList = std::vector<Track*>;
 	enum TrackContainerTypes
 	{
 		PatternContainer,
diff --git a/include/panning.h b/include/panning.h
index 56ca04eee..0fd74d1cc 100644
--- a/include/panning.h
+++ b/include/panning.h
@@ -31,6 +31,8 @@
 #include "Midi.h"
 #include "volume.h"
 
+#include <cmath>
+
 namespace lmms
 {
 
@@ -40,7 +42,7 @@ inline StereoVolumeVector panningToVolumeVector( panning_t _p,
 {
 	StereoVolumeVector v = { { _scale, _scale } };
 	const float pf = _p / 100.0f;
-	v.vol[_p >= PanningCenter ? 0 : 1] *= 1.0f - qAbs<float>( pf );
+	v.vol[_p >= PanningCenter ? 0 : 1] *= 1.0f - std::abs(pf);
 	return v;
 }
 
diff --git a/plugins/PeakControllerEffect/PeakControllerEffect.cpp b/plugins/PeakControllerEffect/PeakControllerEffect.cpp
index d32a22320..bd99631b7 100644
--- a/plugins/PeakControllerEffect/PeakControllerEffect.cpp
+++ b/plugins/PeakControllerEffect/PeakControllerEffect.cpp
@@ -76,7 +76,7 @@ PeakControllerEffect::PeakControllerEffect(
 	{
 		Engine::getSong()->addController( m_autoController );
 	}
-	PeakController::s_effects.append( this );
+	PeakController::s_effects.push_back(this);
 }
 
 
@@ -84,11 +84,11 @@ PeakControllerEffect::PeakControllerEffect(
 
 PeakControllerEffect::~PeakControllerEffect()
 {
-	int idx = PeakController::s_effects.indexOf( this );
-	if( idx >= 0 )
+	auto it = std::find(PeakController::s_effects.begin(), PeakController::s_effects.end(), this);
+	if (it != PeakController::s_effects.end())
 	{
-		PeakController::s_effects.remove( idx );
-		Engine::getSong()->removeController( m_autoController );
+		PeakController::s_effects.erase(it);
+		Engine::getSong()->removeController(m_autoController);
 	}
 }
 
diff --git a/src/core/AudioEngine.cpp b/src/core/AudioEngine.cpp
index a91e88f38..91a16ed12 100644
--- a/src/core/AudioEngine.cpp
+++ b/src/core/AudioEngine.cpp
@@ -419,7 +419,7 @@ const surroundSampleFrame * AudioEngine::renderNextBuffer()
 	}
 
 	// STAGE 2: process effects of all instrument- and sampletracks
-	AudioEngineWorkerThread::fillJobQueue<QVector<AudioPort *> >( m_audioPorts );
+	AudioEngineWorkerThread::fillJobQueue(m_audioPorts);
 	AudioEngineWorkerThread::startAndWaitForJobs();
 
 
@@ -663,7 +663,7 @@ void AudioEngine::removeAudioPort(AudioPort * port)
 {
 	requestChangeInModel();
 
-	QVector<AudioPort *>::Iterator it = std::find(m_audioPorts.begin(), m_audioPorts.end(), port);
+	auto it = std::find(m_audioPorts.begin(), m_audioPorts.end(), port);
 	if (it != m_audioPorts.end())
 	{
 		m_audioPorts.erase(it);
diff --git a/src/core/AutomatableModel.cpp b/src/core/AutomatableModel.cpp
index 378ccd91e..fa4697c69 100644
--- a/src/core/AutomatableModel.cpp
+++ b/src/core/AutomatableModel.cpp
@@ -71,7 +71,7 @@ AutomatableModel::~AutomatableModel()
 {
 	while( m_linkedModels.empty() == false )
 	{
-		m_linkedModels.last()->unlinkModel( this );
+		m_linkedModels.back()->unlinkModel(this);
 		m_linkedModels.erase( m_linkedModels.end() - 1 );
 	}
 
@@ -473,7 +473,8 @@ float AutomatableModel::fittedValue( float value ) const
 
 void AutomatableModel::linkModel( AutomatableModel* model )
 {
-	if( !m_linkedModels.contains( model ) && model != this )
+	auto containsModel = std::find(m_linkedModels.begin(), m_linkedModels.end(), model) != m_linkedModels.end();
+	if (!containsModel && model != this)
 	{
 		m_linkedModels.push_back( model );
 
@@ -490,7 +491,7 @@ void AutomatableModel::linkModel( AutomatableModel* model )
 
 void AutomatableModel::unlinkModel( AutomatableModel* model )
 {
-	AutoModelVector::Iterator it = std::find( m_linkedModels.begin(), m_linkedModels.end(), model );
+	auto it = std::find(m_linkedModels.begin(), m_linkedModels.end(), model);
 	if( it != m_linkedModels.end() )
 	{
 		m_linkedModels.erase( it );
@@ -504,7 +505,8 @@ void AutomatableModel::unlinkModel( AutomatableModel* model )
 
 void AutomatableModel::linkModels( AutomatableModel* model1, AutomatableModel* model2 )
 {
-	if (!model1->m_linkedModels.contains( model2 ) && model1 != model2)
+	auto model1ContainsModel2 = std::find(model1->m_linkedModels.begin(), model1->m_linkedModels.end(), model2) != model1->m_linkedModels.end();
+	if (!model1ContainsModel2 && model1 != model2)
 	{
 		// copy data
 		model1->m_value = model2->m_value;
@@ -588,7 +590,7 @@ float AutomatableModel::controllerValue( int frameOffset ) const
 		return v;
 	}
 
-	AutomatableModel* lm = m_linkedModels.first();
+	AutomatableModel* lm = m_linkedModels.front();
 	if (lm->controllerConnection() && lm->useControllerValue())
 	{
 		return fittedValue( lm->controllerValue( frameOffset ) );
@@ -649,7 +651,7 @@ ValueBuffer * AutomatableModel::valueBuffer()
 		AutomatableModel* lm = nullptr;
 		if (hasLinkedModels())
 		{
-			lm = m_linkedModels.first();
+			lm = m_linkedModels.front();
 		}
 		if (lm && lm->controllerConnection() && lm->useControllerValue() &&
 				lm->controllerConnection()->getController()->isSampleExact())
@@ -721,8 +723,8 @@ void AutomatableModel::reset()
 float AutomatableModel::globalAutomationValueAt( const TimePos& time )
 {
 	// get clips that connect to this model
-	QVector<AutomationClip *> clips = AutomationClip::clipsForModel( this );
-	if( clips.isEmpty() )
+	auto clips = AutomationClip::clipsForModel(this);
+	if (clips.empty())
 	{
 		// if no such clips exist, return current value
 		return m_value;
@@ -731,17 +733,17 @@ float AutomatableModel::globalAutomationValueAt( const TimePos& time )
 	{
 		// of those clips:
 		// find the clips which overlap with the time position
-		QVector<AutomationClip *> clipsInRange;
+		std::vector<AutomationClip*> clipsInRange;
 		for (const auto& clip : clips)
 		{
 			int s = clip->startPosition();
 			int e = clip->endPosition();
-			if (s <= time && e >= time) { clipsInRange += clip; }
+			if (s <= time && e >= time) { clipsInRange.push_back(clip); }
 		}
 
 		AutomationClip * latestClip = nullptr;
 
-		if( ! clipsInRange.isEmpty() )
+		if (!clipsInRange.empty())
 		{
 			// if there are more than one overlapping clips, just use the first one because
 			// multiple clip behaviour is undefined anyway
diff --git a/src/core/AutomationClip.cpp b/src/core/AutomationClip.cpp
index c031c5a41..7a161c355 100644
--- a/src/core/AutomationClip.cpp
+++ b/src/core/AutomationClip.cpp
@@ -120,19 +120,19 @@ bool AutomationClip::addObject( AutomatableModel * _obj, bool _search_dup )
 {
 	QMutexLocker m(&m_clipMutex);
 
-	if( _search_dup && m_objects.contains(_obj) )
+	if (_search_dup && std::find(m_objects.begin(), m_objects.end(), _obj) != m_objects.end())
 	{
 		return false;
 	}
 
 	// the automation track is unconnected and there is nothing in the track
-	if( m_objects.isEmpty() && hasAutomation() == false )
+	if (m_objects.empty() && hasAutomation() == false)
 	{
 		// then initialize first value
 		putValue( TimePos(0), _obj->inverseScaledValue( _obj->value<float>() ), false );
 	}
 
-	m_objects += _obj;
+	m_objects.push_back(_obj);
 
 	connect( _obj, SIGNAL(destroyed(lmms::jo_id_t)),
 			this, SLOT(objectDestroyed(lmms::jo_id_t)),
@@ -184,7 +184,7 @@ const AutomatableModel * AutomationClip::firstObject() const
 	QMutexLocker m(&m_clipMutex);
 
 	AutomatableModel* model;
-	if (!m_objects.isEmpty() && (model = m_objects.first()) != nullptr)
+	if (!m_objects.empty() && (model = m_objects.front()) != nullptr)
 	{
 		return model;
 	}
@@ -380,11 +380,11 @@ void AutomationClip::removeNodes(const int tick0, const int tick1)
 	// Make a list of TimePos with nodes to be removed
 	// because we can't simply remove the nodes from
 	// the timeMap while we are iterating it.
-	QVector<TimePos> nodesToRemove;
+	std::vector<TimePos> nodesToRemove;
 
 	for (auto it = m_timeMap.lowerBound(start), endIt = m_timeMap.upperBound(end); it != endIt; ++it)
 	{
-		nodesToRemove.append(POS(it));
+		nodesToRemove.push_back(POS(it));
 	}
 
 	for (auto node: nodesToRemove)
@@ -831,7 +831,7 @@ void AutomationClip::loadSettings( const QDomElement & _this )
 		}
 		else if( element.tagName() == "object" )
 		{
-			m_idsToResolve << element.attribute( "id" ).toInt();
+			m_idsToResolve.push_back(element.attribute("id").toInt());
 		}
 	}
 	
@@ -865,9 +865,9 @@ QString AutomationClip::name() const
 	{
 		return Clip::name();
 	}
-	if( !m_objects.isEmpty() && m_objects.first() != nullptr )
+	if (!m_objects.empty() && m_objects.front() != nullptr)
 	{
-		return m_objects.first()->fullDisplayName();
+		return m_objects.front()->fullDisplayName();
 	}
 	return tr( "Drag a control while pressing <%1>" ).arg(UI_CTRL_KEY);
 }
@@ -888,12 +888,8 @@ gui::ClipView * AutomationClip::createView( gui::TrackView * _tv )
 
 bool AutomationClip::isAutomated( const AutomatableModel * _m )
 {
-	TrackContainer::TrackList l;
-	l += Engine::getSong()->tracks();
-	l += Engine::patternStore()->tracks();
-	l += Engine::getSong()->globalAutomationTrack();
-
-	for (const auto& track : l)
+	auto l = combineAllTracks();
+	for (const auto track : l)
 	{
 		if (track->type() == Track::AutomationTrack || track->type() == Track::HiddenAutomationTrack)
 		{
@@ -921,16 +917,13 @@ bool AutomationClip::isAutomated( const AutomatableModel * _m )
  * @brief returns a list of all the automation clips that are connected to a specific model
  * @param _m the model we want to look for
  */
-QVector<AutomationClip *> AutomationClip::clipsForModel( const AutomatableModel * _m )
+std::vector<AutomationClip *> AutomationClip::clipsForModel(const AutomatableModel* _m)
 {
-	QVector<AutomationClip*> clips;
-	TrackContainer::TrackList tracks;
-	tracks += Engine::getSong()->tracks();
-	tracks += Engine::patternStore()->tracks();
-	tracks += Engine::getSong()->globalAutomationTrack();
+	std::vector<AutomationClip *> clips;
+	auto l = combineAllTracks();
 
 	// go through all tracks...
-	for (const auto& track : tracks)
+	for (const auto track : l)
 	{
 		// we want only automation tracks...
 		if (track->type() == Track::AutomationTrack || track->type() == Track::HiddenAutomationTrack )
@@ -953,7 +946,7 @@ QVector<AutomationClip *> AutomationClip::clipsForModel( const AutomatableModel
 						}
 					}
 					// if the clips is connected to the model, add it to the list
-					if( has_object ) { clips += a; }
+					if (has_object) { clips.push_back(a); }
 				}
 			}
 		}
@@ -989,9 +982,7 @@ AutomationClip * AutomationClip::globalAutomationClip(
 
 void AutomationClip::resolveAllIDs()
 {
-	TrackContainer::TrackList l = Engine::getSong()->tracks() +
-				Engine::patternStore()->tracks();
-	l += Engine::getSong()->globalAutomationTrack();
+	auto l = combineAllTracks();
 	for (const auto& track : l)
 	{
 		if (track->type() == Track::AutomationTrack || track->type() == Track::HiddenAutomationTrack)
@@ -1060,10 +1051,9 @@ void AutomationClip::objectDestroyed( jo_id_t _id )
 	// when switching samplerate) and real deletions because in the latter
 	// case we had to remove ourselves if we're the global automation
 	// clip of the destroyed object
-	m_idsToResolve += _id;
+	m_idsToResolve.push_back(_id);
 
-	for( objectVector::Iterator objIt = m_objects.begin();
-		objIt != m_objects.end(); objIt++ )
+	for (auto objIt = m_objects.begin(); objIt != m_objects.end(); objIt++)
 	{
 		Q_ASSERT( !(*objIt).isNull() );
 		if( (*objIt)->id() == _id )
@@ -1173,4 +1163,18 @@ void AutomationClip::generateTangents(timeMap::iterator it, int numToGenerate)
 	}
 }
 
+std::vector<Track*> AutomationClip::combineAllTracks()
+{
+	std::vector<Track*> combinedTrackList;
+
+	auto& songTracks = Engine::getSong()->tracks();
+	auto& patternStoreTracks = Engine::patternStore()->tracks();
+
+	combinedTrackList.insert(combinedTrackList.end(), songTracks.begin(), songTracks.end());
+	combinedTrackList.insert(combinedTrackList.end(), patternStoreTracks.begin(), patternStoreTracks.end());
+	combinedTrackList.push_back(Engine::getSong()->globalAutomationTrack());
+
+	return combinedTrackList;
+}
+
 } // namespace lmms
diff --git a/src/core/ConfigManager.cpp b/src/core/ConfigManager.cpp
index bfe9e31f1..c647a27e6 100644
--- a/src/core/ConfigManager.cpp
+++ b/src/core/ConfigManager.cpp
@@ -334,10 +334,9 @@ void ConfigManager::addRecentlyOpenedProject(const QString & file)
 
 
 
-const QString & ConfigManager::value(const QString & cls,
-					const QString & attribute) const
+QString ConfigManager::value(const QString& cls, const QString& attribute, const QString& defaultVal) const
 {
-	if(m_settings.contains(cls))
+	if (m_settings.find(cls) != m_settings.end())
 	{
 		for (const auto& setting : m_settings[cls])
 		{
@@ -347,18 +346,7 @@ const QString & ConfigManager::value(const QString & cls,
 			}
 		}
 	}
-	static QString empty;
-	return empty;
-}
-
-
-
-const QString & ConfigManager::value(const QString & cls,
-				      const QString & attribute,
-				      const QString & defaultVal) const
-{
-	const QString & val = value(cls, attribute);
-	return val.isEmpty() ? defaultVal : val;
+	return defaultVal;
 }
 
 
diff --git a/src/core/Controller.cpp b/src/core/Controller.cpp
index aee6481cc..e7031f20c 100644
--- a/src/core/Controller.cpp
+++ b/src/core/Controller.cpp
@@ -25,8 +25,8 @@
  */
 
 #include <QDomElement>
-#include <QVector>
 
+#include <vector>
 
 #include "AudioEngine.h"
 #include "ControllerConnection.h"
@@ -40,7 +40,7 @@ namespace lmms
 
 
 long Controller::s_periods = 0;
-QVector<Controller *> Controller::s_controllers;
+std::vector<Controller*> Controller::s_controllers;
 
 
 
@@ -55,7 +55,7 @@ Controller::Controller( ControllerTypes _type, Model * _parent,
 {
 	if( _type != DummyController && _type != MidiController )
 	{
-		s_controllers.append( this );
+		s_controllers.push_back(this);
 		// Determine which name to use
 		for ( uint i=s_controllers.size(); ; i++ )
 		{
@@ -86,10 +86,10 @@ Controller::Controller( ControllerTypes _type, Model * _parent,
 
 Controller::~Controller()
 {
-	int idx = s_controllers.indexOf( this );
-	if( idx >= 0 )
+	auto it = std::find(s_controllers.begin(), s_controllers.end(), this);
+	if (it != s_controllers.end())
 	{
-		s_controllers.remove( idx );
+		s_controllers.erase(it);
 	}
 
 	m_valueBuffer.clear();
diff --git a/src/core/ControllerConnection.cpp b/src/core/ControllerConnection.cpp
index c65cd8ae9..a4477c563 100644
--- a/src/core/ControllerConnection.cpp
+++ b/src/core/ControllerConnection.cpp
@@ -53,7 +53,7 @@ ControllerConnection::ControllerConnection(Controller * _controller) :
 		m_controller = Controller::create( Controller::DummyController,
 									nullptr );
 	}
-	s_connections.append( this );
+	s_connections.push_back(this);
 }
 
 
@@ -64,7 +64,7 @@ ControllerConnection::ControllerConnection( int _controllerId ) :
 	m_controllerId( _controllerId ),
 	m_ownsController( false )
 {
-	s_connections.append( this );
+	s_connections.push_back(this);
 }
 
 
@@ -76,7 +76,10 @@ ControllerConnection::~ControllerConnection()
 	{
 		m_controller->removeConnection( this );
 	}
-	s_connections.remove( s_connections.indexOf( this ) );
+
+	auto it = std::find(s_connections.begin(), s_connections.end(), this);
+	if (it != s_connections.end()) { s_connections.erase(it); };
+
 	if( m_ownsController )
 	{
 		delete m_controller;
@@ -186,10 +189,12 @@ void ControllerConnection::saveSettings( QDomDocument & _doc, QDomElement & _thi
 		}
 		else
 		{
-			int id = Engine::getSong()->controllers().indexOf( m_controller );
-			if( id >= 0 )
+			const auto& controllers = Engine::getSong()->controllers();
+			const auto it = std::find(controllers.begin(), controllers.end(), m_controller);
+			if (it != controllers.end())
 			{
-				_this.setAttribute( "id", id );
+				const int id = std::distance(controllers.begin(), it);
+				_this.setAttribute("id", id);
 			}
 		}
 	}
diff --git a/src/core/EffectChain.cpp b/src/core/EffectChain.cpp
index 024ddab64..b07a7227b 100644
--- a/src/core/EffectChain.cpp
+++ b/src/core/EffectChain.cpp
@@ -56,7 +56,7 @@ EffectChain::~EffectChain()
 void EffectChain::saveSettings( QDomDocument & _doc, QDomElement & _this )
 {
 	m_enabledModel.saveSettings( _doc, _this, "enabled" );
-	_this.setAttribute( "numofeffects", m_effects.count() );
+	_this.setAttribute("numofeffects", static_cast<int>(m_effects.size()));
 
 	for( Effect* effect : m_effects)
 	{
@@ -121,7 +121,7 @@ void EffectChain::loadSettings( const QDomElement & _this )
 void EffectChain::appendEffect( Effect * _effect )
 {
 	Engine::audioEngine()->requestChangeInModel();
-	m_effects.append( _effect );
+	m_effects.push_back(_effect);
 	Engine::audioEngine()->doneChangeInModel();
 
 	m_enabledModel.setValue( true );
@@ -136,7 +136,7 @@ void EffectChain::removeEffect( Effect * _effect )
 {
 	Engine::audioEngine()->requestChangeInModel();
 
-	Effect ** found = std::find( m_effects.begin(), m_effects.end(), _effect );
+	auto found = std::find(m_effects.begin(), m_effects.end(), _effect);
 	if( found == m_effects.end() )
 	{
 		Engine::audioEngine()->doneChangeInModel();
@@ -146,7 +146,7 @@ void EffectChain::removeEffect( Effect * _effect )
 
 	Engine::audioEngine()->doneChangeInModel();
 
-	if( m_effects.isEmpty() )
+	if (m_effects.empty())
 	{
 		m_enabledModel.setValue( false );
 	}
@@ -159,10 +159,10 @@ void EffectChain::removeEffect( Effect * _effect )
 
 void EffectChain::moveDown( Effect * _effect )
 {
-	if( _effect != m_effects.last() )
+	if (_effect != m_effects.back())
 	{
-		int i = m_effects.indexOf(_effect);
-		std::swap(m_effects[i + 1], m_effects[i]);
+		auto it = std::find(m_effects.begin(), m_effects.end(), _effect);
+		std::swap(*std::next(it), *it);
 	}
 }
 
@@ -171,10 +171,10 @@ void EffectChain::moveDown( Effect * _effect )
 
 void EffectChain::moveUp( Effect * _effect )
 {
-	if( _effect != m_effects.first() )
+	if (_effect != m_effects.front())
 	{
-		int i = m_effects.indexOf(_effect);
-		std::swap(m_effects[i - 1], m_effects[i]);
+		auto it = std::find(m_effects.begin(), m_effects.end(), _effect);
+		std::swap(*std::prev(it), *it);
 	}
 }
 
@@ -228,9 +228,9 @@ void EffectChain::clear()
 
 	Engine::audioEngine()->requestChangeInModel();
 
-	while( m_effects.count() )
+	while (m_effects.size())
 	{
-		Effect * e = m_effects[m_effects.count() - 1];
+		auto e = m_effects[m_effects.size() - 1];
 		m_effects.pop_back();
 		delete e;
 	}
diff --git a/src/core/InstrumentFunctions.cpp b/src/core/InstrumentFunctions.cpp
index 06e56666c..d2fea9dbd 100644
--- a/src/core/InstrumentFunctions.cpp
+++ b/src/core/InstrumentFunctions.cpp
@@ -177,12 +177,11 @@ bool InstrumentFunctionNoteStacking::Chord::hasSemiTone( int8_t semi_tone ) cons
 
 
 
-InstrumentFunctionNoteStacking::ChordTable::ChordTable() :
-	QVector<Chord>()
+InstrumentFunctionNoteStacking::ChordTable::ChordTable()
 {
 	for (const auto& chord : s_initTable)
 	{
-		push_back(Chord(chord.m_name, chord.m_semiTones));
+		m_chords.emplace_back(chord.m_name, chord.m_semiTones);
 	}
 }
 
@@ -191,10 +190,12 @@ InstrumentFunctionNoteStacking::ChordTable::ChordTable() :
 
 const InstrumentFunctionNoteStacking::Chord & InstrumentFunctionNoteStacking::ChordTable::getByName( const QString & name, bool is_scale ) const
 {
-	for( int i = 0; i < size(); i++ )
+	for (const auto& chord : m_chords)
 	{
-		if( at( i ).getName() == name && is_scale == at( i ).isScale() )
-			return at( i );
+		if (chord.getName() == name && is_scale == chord.isScale())
+		{
+			return chord;
+		}
 	}
 
 	static Chord empty;
@@ -211,9 +212,10 @@ InstrumentFunctionNoteStacking::InstrumentFunctionNoteStacking( Model * _parent
 	m_chordRangeModel( 1.0f, 1.0f, 9.0f, 1.0f, this, tr( "Chord range" ) )
 {
 	const ChordTable & chord_table = ChordTable::getInstance();
-	for( int i = 0; i < chord_table.size(); ++i )
+
+	for (const auto& chord : chord_table.chords())
 	{
-		m_chordsModel.addItem( chord_table[i].getName() );
+		m_chordsModel.addItem(chord.getName());
 	}
 }
 
@@ -244,10 +246,10 @@ void InstrumentFunctionNoteStacking::processNote( NotePlayHandle * _n )
 			const int sub_note_key_base = base_note_key + octave_cnt * KeysPerOctave;
 
 			// process all notes in the chord
-			for( int i = 0; i < chord_table[selected_chord].size(); ++i )
+			for( int i = 0; i < chord_table.chords()[selected_chord].size(); ++i )
 			{
 				// add interval to sub-note-key
-				const int sub_note_key = sub_note_key_base + (int) chord_table[selected_chord][i];
+				const int sub_note_key = sub_note_key_base + (int) chord_table.chords()[selected_chord][i];
 				// maybe we're out of range -> let's get outta
 				// here!
 				if( sub_note_key > NumKeys )
@@ -309,9 +311,9 @@ InstrumentFunctionArpeggio::InstrumentFunctionArpeggio( Model * _parent ) :
 	m_arpModeModel( this, tr( "Arpeggio mode" ) )
 {
 	const InstrumentFunctionNoteStacking::ChordTable & chord_table = InstrumentFunctionNoteStacking::ChordTable::getInstance();
-	for( int i = 0; i < chord_table.size(); ++i )
+	for (auto& chord : chord_table.chords())
 	{
-		m_arpModel.addItem( chord_table[i].getName() );
+		m_arpModel.addItem(chord.getName());
 	}
 
 	m_arpDirectionModel.addItem( tr( "Up" ), std::make_unique<PixmapLoader>( "arp_up" ) );
@@ -362,7 +364,7 @@ void InstrumentFunctionArpeggio::processNote( NotePlayHandle * _n )
 	}
 
 	const InstrumentFunctionNoteStacking::ChordTable & chord_table = InstrumentFunctionNoteStacking::ChordTable::getInstance();
-	const int cur_chord_size = chord_table[selected_arp].size();
+	const int cur_chord_size = chord_table.chords()[selected_arp].size();
 	const int range = static_cast<int>(cur_chord_size * m_arpRangeModel.value() * m_arpRepeatsModel.value());
 	const int total_range = range * cnphv.size();
 
@@ -485,7 +487,7 @@ void InstrumentFunctionArpeggio::processNote( NotePlayHandle * _n )
 
 		// now calculate final key for our arp-note
 		const int sub_note_key = base_note_key + (cur_arp_idx / cur_chord_size ) *
-							KeysPerOctave + chord_table[selected_arp][cur_arp_idx % cur_chord_size];
+							KeysPerOctave + chord_table.chords()[selected_arp][cur_arp_idx % cur_chord_size];
 
 		// range-checking
 		if( sub_note_key >= NumKeys ||
diff --git a/src/core/Mixer.cpp b/src/core/Mixer.cpp
index b2a9f9e3f..dba5c334e 100644
--- a/src/core/Mixer.cpp
+++ b/src/core/Mixer.cpp
@@ -201,9 +201,9 @@ Mixer::Mixer() :
 
 Mixer::~Mixer()
 {
-	while( ! m_mixerRoutes.isEmpty() )
+	while (!m_mixerRoutes.empty())
 	{
-		deleteChannelSend( m_mixerRoutes.first() );
+		deleteChannelSend(m_mixerRoutes.front());
 	}
 	while( m_mixerChannels.size() )
 	{
@@ -293,8 +293,11 @@ void Mixer::deleteChannel( int index )
 
 	// go through every instrument and adjust for the channel index change
 	TrackContainer::TrackList tracks;
-	tracks += Engine::getSong()->tracks();
-	tracks += Engine::patternStore()->tracks();
+
+	auto& songTracks = Engine::getSong()->tracks();
+	auto& patternStoreTracks = Engine::patternStore()->tracks();
+	tracks.insert(tracks.end(), songTracks.begin(), songTracks.end());
+	tracks.insert(tracks.end(), patternStoreTracks.begin(), patternStoreTracks.end());
 
 	for( Track* t : tracks )
 	{
@@ -335,13 +338,13 @@ void Mixer::deleteChannel( int index )
 	MixerChannel * ch = m_mixerChannels[index];
 
 	// delete all of this channel's sends and receives
-	while( ! ch->m_sends.isEmpty() )
+	while (!ch->m_sends.empty())
 	{
-		deleteChannelSend( ch->m_sends.first() );
+		deleteChannelSend(ch->m_sends.front());
 	}
-	while( ! ch->m_receives.isEmpty() )
+	while (!ch->m_receives.empty())
 	{
-		deleteChannelSend( ch->m_receives.first() );
+		deleteChannelSend(ch->m_receives.front());
 	}
 
 	// if m_lastSoloed was our index, reset it
@@ -350,7 +353,7 @@ void Mixer::deleteChannel( int index )
 	else if (m_lastSoloed > index) { --m_lastSoloed; }
 
 	// actually delete the channel
-	m_mixerChannels.remove(index);
+	m_mixerChannels.erase(m_mixerChannels.begin() + index);
 	delete ch;
 
 	for( int i = index; i < m_mixerChannels.size(); ++i )
@@ -477,13 +480,13 @@ MixerRoute * Mixer::createRoute( MixerChannel * from, MixerChannel * to, float a
 	auto route = new MixerRoute(from, to, amount);
 
 	// add us to from's sends
-	from->m_sends.append( route );
+	from->m_sends.push_back(route);
 
 	// add us to to's receives
-	to->m_receives.append( route );
+	to->m_receives.push_back(route);
 
 	// add us to mixer's list
-	Engine::mixer()->m_mixerRoutes.append( route );
+	Engine::mixer()->m_mixerRoutes.push_back(route);
 	Engine::audioEngine()->doneChangeInModel();
 
 	return route;
@@ -512,12 +515,22 @@ void Mixer::deleteChannelSend( mix_ch_t fromChannel, mix_ch_t toChannel )
 void Mixer::deleteChannelSend( MixerRoute * route )
 {
 	Engine::audioEngine()->requestChangeInModel();
+
+	auto removeFromMixerRoute = [route](MixerRouteVector& routeVec)
+	{
+		auto it = std::find(routeVec.begin(), routeVec.end(), route);
+		if (it != routeVec.end()) { routeVec.erase(it); }
+	};
+
 	// remove us from from's sends
-	route->sender()->m_sends.remove( route->sender()->m_sends.indexOf( route ) );
+	removeFromMixerRoute(route->sender()->m_sends);
+
 	// remove us from to's receives
-	route->receiver()->m_receives.remove( route->receiver()->m_receives.indexOf( route ) );
+	removeFromMixerRoute(route->receiver()->m_receives);
+
 	// remove us from mixer's list
-	Engine::mixer()->m_mixerRoutes.remove( Engine::mixer()->m_mixerRoutes.indexOf( route ) );
+	removeFromMixerRoute(Engine::mixer()->m_mixerRoutes);
+
 	delete route;
 	Engine::audioEngine()->doneChangeInModel();
 }
@@ -714,9 +727,9 @@ void Mixer::clearChannel(mix_ch_t index)
 	if( index > 0)
 	{
 		// delete existing sends
-		while( ! ch->m_sends.isEmpty() )
+		while (!ch->m_sends.empty())
 		{
-			deleteChannelSend( ch->m_sends.first() );
+			deleteChannelSend(ch->m_sends.front());
 		}
 
 		// add send to master
@@ -724,9 +737,9 @@ void Mixer::clearChannel(mix_ch_t index)
 	}
 
 	// delete receives
-	while( ! ch->m_receives.isEmpty() )
+	while (!ch->m_receives.empty())
 	{
-		deleteChannelSend( ch->m_receives.first() );
+		deleteChannelSend(ch->m_receives.front());
 	}
 }
 
@@ -835,15 +848,18 @@ void Mixer::validateChannelName( int index, int oldIndex )
 bool Mixer::isChannelInUse(int index)
 {
 	// check if the index mixer channel receives audio from any other channel
-	if (!m_mixerChannels[index]->m_receives.isEmpty())
+	if (!m_mixerChannels[index]->m_receives.empty())
 	{
 		return true;
 	}
 
 	// check if the destination mixer channel on any instrument or sample track is the index mixer channel
 	TrackContainer::TrackList tracks;
-	tracks += Engine::getSong()->tracks();
-	tracks += Engine::patternStore()->tracks();
+
+	auto& songTracks = Engine::getSong()->tracks();
+	auto& patternStoreTracks = Engine::patternStore()->tracks();
+	tracks.insert(tracks.end(), songTracks.begin(), songTracks.end());
+	tracks.insert(tracks.end(), patternStoreTracks.begin(), patternStoreTracks.end());
 
 	for (const auto t : tracks)
 	{
diff --git a/src/core/PeakController.cpp b/src/core/PeakController.cpp
index a9215325e..af0e7e69d 100644
--- a/src/core/PeakController.cpp
+++ b/src/core/PeakController.cpp
@@ -161,12 +161,11 @@ void PeakController::loadSettings( const QDomElement & _this )
 		effectId = m_loadCount++;
 	}
 
-	PeakControllerEffectVector::Iterator i;
-	for( i = s_effects.begin(); i != s_effects.end(); ++i )
+	for (const auto& effect : s_effects)
 	{
-		if( (*i)->m_effectId == effectId )
+		if (effect->m_effectId == effectId)
 		{
-			m_peakEffect = *i;
+			m_peakEffect = effect;
 			return;
 		}
 	}
@@ -190,16 +189,14 @@ PeakController * PeakController::getControllerBySetting(const QDomElement & _thi
 {
 	int effectId = _this.attribute( "effectId" ).toInt();
 
-	PeakControllerEffectVector::Iterator i;
-
 	//Backward compatibility for bug in <= 0.4.15 . For >= 1.0.0 ,
 	//foundCount should always be 1 because m_effectId is initialized with rand()
 	int foundCount = 0;
 	if( m_buggedFile == false )
 	{
-		for( i = s_effects.begin(); i != s_effects.end(); ++i )
+		for (const auto& effect : s_effects)
 		{
-			if( (*i)->m_effectId == effectId )
+			if (effect->m_effectId == effectId)
 			{
 				foundCount++;
 			}
@@ -208,9 +205,9 @@ PeakController * PeakController::getControllerBySetting(const QDomElement & _thi
 		{
 			m_buggedFile = true;
 			int newEffectId = 0;
-			for( i = s_effects.begin(); i != s_effects.end(); ++i )
+			for (const auto& effect : s_effects)
 			{
-				(*i)->m_effectId = newEffectId++;
+				effect->m_effectId = newEffectId++;
 			}
 			QMessageBox msgBox;
 			msgBox.setIcon( QMessageBox::Information );
@@ -231,11 +228,11 @@ PeakController * PeakController::getControllerBySetting(const QDomElement & _thi
 	}
 	m_getCount++; //NB: m_getCount should be increased even m_buggedFile is false
 
-	for( i = s_effects.begin(); i != s_effects.end(); ++i )
+	for (const auto& effect : s_effects)
 	{
-		if( (*i)->m_effectId == effectId )
+		if (effect->m_effectId == effectId)
 		{
-			return (*i)->controller();
+			return effect->controller();
 		}
 	}
 
diff --git a/src/core/RenderManager.cpp b/src/core/RenderManager.cpp
index 56b4ce9d7..8c031b970 100644
--- a/src/core/RenderManager.cpp
+++ b/src/core/RenderManager.cpp
@@ -69,7 +69,7 @@ void RenderManager::renderNextTrack()
 {
 	m_activeRenderer.reset();
 
-	if( m_tracksToRender.isEmpty() )
+	if (m_tracksToRender.empty())
 	{
 		// nothing left to render
 		restoreMutedState();
@@ -169,7 +169,7 @@ void RenderManager::render(QString outputPath)
 // Unmute all tracks that were muted while rendering tracks
 void RenderManager::restoreMutedState()
 {
-	while( !m_unmuted.isEmpty() )
+	while (!m_unmuted.empty())
 	{
 		Track* restoreTrack = m_unmuted.back();
 		m_unmuted.pop_back();
diff --git a/src/core/Song.cpp b/src/core/Song.cpp
index fef66f193..6f4c5212e 100644
--- a/src/core/Song.cpp
+++ b/src/core/Song.cpp
@@ -840,7 +840,9 @@ bpm_t Song::getTempo()
 
 AutomatedValueMap Song::automatedValuesAt(TimePos time, int clipNum) const
 {
-	return TrackContainer::automatedValuesFromTracks(TrackList{m_globalAutomationTrack} << tracks(), time, clipNum);
+	auto trackList = TrackList{m_globalAutomationTrack};
+	trackList.insert(trackList.end(), tracks().begin(), tracks().end());
+	return TrackContainer::automatedValuesFromTracks(trackList, time, clipNum);
 }
 
 
@@ -1326,8 +1328,7 @@ void Song::restoreControllerStates( const QDomElement & element )
 		else
 		{
 			// Fix indices to ensure correct connections
-			m_controllers.append(Controller::create(
-				Controller::DummyController, this));
+			m_controllers.push_back(Controller::create(Controller::DummyController, this));
 		}
 
 		node = node.nextSibling();
@@ -1445,9 +1446,10 @@ void Song::setProjectFileName(QString const & projectFileName)
 
 void Song::addController( Controller * controller )
 {
-	if( controller && !m_controllers.contains( controller ) )
+	bool containsController = std::find(m_controllers.begin(), m_controllers.end(), controller) != m_controllers.end();
+	if (controller && !containsController)
 	{
-		m_controllers.append( controller );
+		m_controllers.push_back(controller);
 		emit controllerAdded( controller );
 
 		this->setModified();
@@ -1459,10 +1461,10 @@ void Song::addController( Controller * controller )
 
 void Song::removeController( Controller * controller )
 {
-	int index = m_controllers.indexOf( controller );
-	if( index != -1 )
+	auto it = std::find(m_controllers.begin(), m_controllers.end(), controller);
+	if (it != m_controllers.end())
 	{
-		m_controllers.remove( index );
+		m_controllers.erase(it);
 
 		emit controllerRemoved( controller );
 		delete controller;
diff --git a/src/core/StepRecorder.cpp b/src/core/StepRecorder.cpp
index e8f31f644..9c2a216ae 100644
--- a/src/core/StepRecorder.cpp
+++ b/src/core/StepRecorder.cpp
@@ -91,7 +91,7 @@ void StepRecorder::notePressed(const Note & n)
 	StepNote* stepNote = findCurStepNote(n.key());
 	if(stepNote == nullptr)
 	{
-		m_curStepNotes.append(new StepNote(Note(m_curStepLength, m_curStepStartPos, n.key(), n.getVolume(), n.getPanning())));
+		m_curStepNotes.push_back(new StepNote(Note(m_curStepLength, m_curStepStartPos, n.key(), n.getVolume(), n.getPanning())));
 		m_pianoRoll.update();
 	}
 	else if (stepNote->isReleased())
@@ -175,15 +175,15 @@ void StepRecorder::setStepsLength(const TimePos& newLength)
 	updateWidget();
 }
 
-QVector<Note*> StepRecorder::getCurStepNotes()
+std::vector<Note*> StepRecorder::getCurStepNotes()
 {
-	QVector<Note*> notes;
+	std::vector<Note*> notes;
 
 	if(m_isStepInProgress)
 	{
-		for(StepNote* stepNote: m_curStepNotes)
+		for (StepNote* stepNote: m_curStepNotes)
 		{
-			notes.append(&stepNote->m_note);
+			notes.push_back(&stepNote->m_note);
 		}
 	}
 
@@ -288,18 +288,13 @@ void StepRecorder::removeNotesReleasedForTooLong()
 	int nextTimout = std::numeric_limits<int>::max();
 	bool notesRemoved = false;
 
-	QMutableVectorIterator<StepNote*> itr(m_curStepNotes);
-	while (itr.hasNext())
+	for (const auto& stepNote : m_curStepNotes)
 	{
-		StepNote* stepNote = itr.next();
-
-		if(stepNote->isReleased())
+		if (stepNote->isReleased())
 		{
 			const int timeSinceReleased = stepNote->timeSinceReleased(); // capture value to avoid wraparound when calculting nextTimout
 			if (timeSinceReleased >= REMOVE_RELEASED_NOTE_TIME_THRESHOLD_MS)
 			{
-				delete stepNote;
-				itr.remove();
 				notesRemoved = true;
 			}
 			else
@@ -309,6 +304,17 @@ void StepRecorder::removeNotesReleasedForTooLong()
 		}
 	}
 
+	m_curStepNotes.erase(std::remove_if(m_curStepNotes.begin(), m_curStepNotes.end(), [](auto stepNote)
+	{
+		bool shouldRemove = stepNote->isReleased() && stepNote->timeSinceReleased() >= REMOVE_RELEASED_NOTE_TIME_THRESHOLD_MS;
+		if (shouldRemove)
+		{
+			delete stepNote;
+		}
+
+		return shouldRemove;
+	}), m_curStepNotes.end());
+
 	if(notesRemoved)
 	{
 		m_pianoRoll.update();
diff --git a/src/core/Track.cpp b/src/core/Track.cpp
index 084f302f8..33b9c8ef3 100644
--- a/src/core/Track.cpp
+++ b/src/core/Track.cpp
@@ -84,9 +84,9 @@ Track::~Track()
 	lock();
 	emit destroyedTrack();
 
-	while( !m_clips.isEmpty() )
+	while (!m_clips.empty())
 	{
-		delete m_clips.last();
+		delete m_clips.back();
 	}
 
 	m_trackContainer->removeTrack( this );
@@ -365,9 +365,9 @@ void Track::removeClip( Clip * clip )
 /*! \brief Remove all Clips from this track */
 void Track::deleteClips()
 {
-	while( ! m_clips.isEmpty() )
+	while (!m_clips.empty())
 	{
-		delete m_clips.first();
+		delete m_clips.front();
 	}
 }
 
diff --git a/src/core/TrackContainer.cpp b/src/core/TrackContainer.cpp
index 0347773ed..33c695f48 100644
--- a/src/core/TrackContainer.cpp
+++ b/src/core/TrackContainer.cpp
@@ -196,14 +196,14 @@ void TrackContainer::removeTrack( Track * _track )
 	//   After checking that index != -1, we need to upgrade the lock to a write locker before changing m_tracks.
 	//   But since Qt offers no function to promote a read lock to a write lock, we must start with the write locker.
 	QWriteLocker lockTracksAccess(&m_tracksMutex);
-	int index = m_tracks.indexOf( _track );
-	if( index != -1 )
+	auto it = std::find(m_tracks.begin(), m_tracks.end(), _track);
+	if (it != m_tracks.end())
 	{
 		// If the track is solo, all other tracks are muted. Change this before removing the solo track:
 		if (_track->isSolo()) {
 			_track->setSolo(false);
 		}
-		m_tracks.remove( index );
+		m_tracks.erase(it);
 		lockTracksAccess.unlock();
 
 		if( Engine::getSong() )
@@ -226,9 +226,9 @@ void TrackContainer::updateAfterTrackAdd()
 void TrackContainer::clearAllTracks()
 {
 	//m_tracksMutex.lockForWrite();
-	while( !m_tracks.isEmpty() )
+	while (!m_tracks.empty())
 	{
-		delete m_tracks.first();
+		delete m_tracks.front();
 	}
 	//m_tracksMutex.unlock();
 }
@@ -240,7 +240,7 @@ bool TrackContainer::isEmpty() const
 {
 	for (const auto& track : m_tracks)
 	{
-		if (!track->getClips().isEmpty())
+		if (!track->getClips().empty())
 		{
 			return false;
 		}
@@ -275,7 +275,7 @@ AutomatedValueMap TrackContainer::automatedValuesFromTracks(const TrackList &tra
 				track->getClipsInRange(clips, 0, time);
 			} else {
 				Q_ASSERT(track->numOfClips() > clipNum);
-				clips << track->getClip(clipNum);
+				clips.push_back(track->getClip(clipNum));
 			}
 		default:
 			break;
diff --git a/src/core/midi/MidiClient.cpp b/src/core/midi/MidiClient.cpp
index 78691de6f..030384c5e 100644
--- a/src/core/midi/MidiClient.cpp
+++ b/src/core/midi/MidiClient.cpp
@@ -71,8 +71,7 @@ void MidiClient::removePort( MidiPort* port )
 		return;
 	}
 
-	QVector<MidiPort *>::Iterator it =
-		std::find( m_midiPorts.begin(), m_midiPorts.end(), port );
+	auto it = std::find(m_midiPorts.begin(), m_midiPorts.end(), port);
 	if( it != m_midiPorts.end() )
 	{
 		m_midiPorts.erase( it );
diff --git a/src/gui/clips/AutomationClipView.cpp b/src/gui/clips/AutomationClipView.cpp
index 6fa91efdb..a5d415a2e 100644
--- a/src/gui/clips/AutomationClipView.cpp
+++ b/src/gui/clips/AutomationClipView.cpp
@@ -191,10 +191,10 @@ void AutomationClipView::constructContextMenu( QMenu * _cm )
 	_cm->addAction( embed::getIconPixmap( "flip_x" ),
 						tr( "Flip Horizontally (Visible)" ),
 						this, SLOT(flipX()));
-	if( !m_clip->m_objects.isEmpty() )
+	if (!m_clip->m_objects.empty())
 	{
 		_cm->addSeparator();
-		auto m = new QMenu(tr("%1 Connections").arg(m_clip->m_objects.count()), _cm);
+		auto m = new QMenu(tr("%1 Connections").arg(m_clip->m_objects.size()), _cm);
 		for (const auto& object : m_clip->m_objects)
 		{
 			if (object)
diff --git a/src/gui/clips/ClipView.cpp b/src/gui/clips/ClipView.cpp
index 8c4f704bc..871466a55 100644
--- a/src/gui/clips/ClipView.cpp
+++ b/src/gui/clips/ClipView.cpp
@@ -545,7 +545,7 @@ DataFile ClipView::createClipDataFiles(
 	{
 		// Insert into the dom under the "clips" element
 		Track* clipTrack = clipView->m_trackView->getTrack();
-		int trackIndex = tc->tracks().indexOf( clipTrack );
+		int trackIndex = std::distance(tc->tracks().begin(), std::find(tc->tracks().begin(), tc->tracks().end(), clipTrack));
 		QDomElement clipElement = dataFile.createElement("clip");
 		clipElement.setAttribute( "trackIndex", trackIndex );
 		clipElement.setAttribute( "trackType", clipTrack->type() );
@@ -557,12 +557,15 @@ DataFile ClipView::createClipDataFiles(
 	dataFile.content().appendChild( clipParent );
 
 	// Add extra metadata needed for calculations later
-	int initialTrackIndex = tc->tracks().indexOf( t );
-	if( initialTrackIndex < 0 )
+
+	const auto initialTrackIt = std::find(tc->tracks().begin(), tc->tracks().end(), t);
+	if (initialTrackIt != tc->tracks().end())
 	{
 		printf("Failed to find selected track in the TrackContainer.\n");
 		return dataFile;
 	}
+
+	const int initialTrackIndex = std::distance(tc->tracks().begin(), initialTrackIt);
 	QDomElement metadata = dataFile.createElement( "copyMetadata" );
 	// initialTrackIndex is the index of the track that was touched
 	metadata.setAttribute( "initialTrackIndex", initialTrackIndex );
diff --git a/src/gui/editors/AutomationEditor.cpp b/src/gui/editors/AutomationEditor.cpp
index db56557a4..1289c5626 100644
--- a/src/gui/editors/AutomationEditor.cpp
+++ b/src/gui/editors/AutomationEditor.cpp
@@ -72,7 +72,7 @@ QPixmap * AutomationEditor::s_toolMove = nullptr;
 QPixmap * AutomationEditor::s_toolYFlip = nullptr;
 QPixmap * AutomationEditor::s_toolXFlip = nullptr;
 
-const QVector<float> AutomationEditor::m_zoomXLevels =
+const std::array<float, 7> AutomationEditor::m_zoomXLevels =
 		{ 0.125f, 0.25f, 0.5f, 1.0f, 2.0f, 4.0f, 8.0f };
 
 
diff --git a/src/gui/editors/PianoRoll.cpp b/src/gui/editors/PianoRoll.cpp
index 337b36b36..753dfe77f 100644
--- a/src/gui/editors/PianoRoll.cpp
+++ b/src/gui/editors/PianoRoll.cpp
@@ -148,15 +148,14 @@ std::array<PianoRoll::PianoRollKeyTypes, 12> PianoRoll::prKeyOrder
 
 const int DEFAULT_PR_PPB = DEFAULT_CELL_WIDTH * DefaultStepsPerBar;
 
-const QVector<float> PianoRoll::m_zoomLevels =
+const std::vector<float> PianoRoll::m_zoomLevels =
 		{0.125f, 0.25f, 0.5f, 1.0f, 1.5f, 2.0f, 4.0f, 8.0f};
 
-const QVector<float> PianoRoll::m_zoomYLevels =
+const std::vector<float> PianoRoll::m_zoomYLevels =
 		{0.25f, 0.5f, 1.0f, 1.5f, 2.0f, 2.5f, 3.0f, 4.0f};
 
 
 PianoRoll::PianoRoll() :
-	m_nemStr( QVector<QString>() ),
 	m_noteEditMenu( nullptr ),
 	m_semiToneMarkerMenu( nullptr ),
 	m_zoomingModel(),
@@ -406,7 +405,7 @@ PianoRoll::PianoRoll() :
 			InstrumentFunctionNoteStacking::ChordTable::getInstance();
 
 	m_scaleModel.addItem( tr("No scale") );
-	for( const InstrumentFunctionNoteStacking::Chord& chord : chord_table )
+	for (const InstrumentFunctionNoteStacking::Chord& chord : chord_table.chords())
 	{
 		if( chord.isScale() )
 		{
@@ -423,7 +422,7 @@ PianoRoll::PianoRoll() :
 
 	// Set up chord model
 	m_chordModel.addItem( tr("No chord") );
-	for( const InstrumentFunctionNoteStacking::Chord& chord : chord_table )
+	for (const InstrumentFunctionNoteStacking::Chord& chord : chord_table.chords())
 	{
 		if( ! chord.isScale() )
 		{
@@ -775,7 +774,7 @@ void PianoRoll::fitNoteLengths(bool fill)
 		{
 			if (!fill) { break; }
 			// Last notes stretch to end of last bar
-			length = notes.last()->endPos().nextFullBar() * TimePos::ticksPerBar() - note->pos();
+			length = notes.back()->endPos().nextFullBar() * TimePos::ticksPerBar() - note->pos();
 		}
 		else
 		{
@@ -1241,11 +1240,11 @@ void PianoRoll::shiftPos(NoteVector notes, int amount)
 {
 	m_midiClip->addJournalCheckPoint();
 
-	if (notes.isEmpty()) {
+	if (notes.empty()) {
 		return;
 	}
 
-	auto leftMostPos = notes.first()->pos();
+	auto leftMostPos = notes.front()->pos();
 	//Limit leftwards shifts to prevent moving left of clip start
 	auto shiftAmount = (leftMostPos > -amount) ? amount : -leftMostPos;
 	if (shiftAmount == 0) { return; }
@@ -1645,7 +1644,7 @@ void PianoRoll::mousePressEvent(QMouseEvent * me )
 
 		if (note)
 		{
-			n.append(note);
+			n.push_back(note);
 
 			updateKnifePos(me);
 
@@ -1723,7 +1722,7 @@ void PianoRoll::mousePressEvent(QMouseEvent * me )
 			const NoteVector & notes = m_midiClip->notes();
 
 			// will be our iterator in the following loop
-			NoteVector::ConstIterator it = notes.begin()+notes.size()-1;
+			auto it = notes.begin() + notes.size() - 1;
 
 			// loop through whole note-vector...
 			for( int i = 0; i < notes.size(); ++i )
@@ -1846,9 +1845,9 @@ void PianoRoll::mousePressEvent(QMouseEvent * me )
 
 				auto selectedNotes = getSelectedNotes();
 
-				m_moveBoundaryLeft = selectedNotes.first()->pos().getTicks();
-				m_moveBoundaryRight = selectedNotes.first()->endPos();
-				m_moveBoundaryBottom = selectedNotes.first()->key();
+				m_moveBoundaryLeft = selectedNotes.front()->pos().getTicks();
+				m_moveBoundaryRight = selectedNotes.front()->endPos();
+				m_moveBoundaryBottom = selectedNotes.front()->key();
 				m_moveBoundaryTop = m_moveBoundaryBottom;
 
 				//Figure out the bounding box of all the selected notes
@@ -2036,7 +2035,7 @@ void PianoRoll::mouseDoubleClickEvent(QMouseEvent * me )
 		{
 			if( i->withinRange( ticks_start, ticks_end ) || ( i->selected() && !altPressed ) )
 			{
-				nv += i;
+				nv.push_back(i);
 			}
 		}
 		// make sure we're on a note
@@ -2054,8 +2053,8 @@ void PianoRoll::mouseDoubleClickEvent(QMouseEvent * me )
 					if( dist < closest_dist ) { closest = i; closest_dist = dist; }
 				}
 				// ... then remove all notes from the vector that aren't on the same exact time
-				NoteVector::Iterator it = nv.begin();
-				while( it != nv.end() )
+				auto it = nv.begin();
+				while (it != nv.end())
 				{
 					const Note *note = *it;
 					if( note->pos().getTicks() != closest->pos().getTicks() )
@@ -2517,7 +2516,7 @@ void PianoRoll::mouseMoveEvent( QMouseEvent * me )
 			bool altPressed = me->modifiers() & Qt::AltModifier;
 			// We iterate from last note in MIDI clip to the first,
 			// chronologically
-			NoteVector::ConstIterator it = notes.begin()+notes.size()-1;
+			auto it = notes.begin() + notes.size() - 1;
 			for( int i = 0; i < notes.size(); ++i )
 			{
 				Note* n = *it;
@@ -2579,7 +2578,7 @@ void PianoRoll::mouseMoveEvent( QMouseEvent * me )
 			const NoteVector & notes = m_midiClip->notes();
 
 			// will be our iterator in the following loop
-			NoteVector::ConstIterator it = notes.begin()+notes.size()-1;
+			auto it = notes.begin() + notes.size() - 1;
 
 			// loop through whole note-vector...
 			for( int i = 0; i < notes.size(); ++i )
@@ -2656,7 +2655,7 @@ void PianoRoll::mouseMoveEvent( QMouseEvent * me )
 			const NoteVector & notes = m_midiClip->notes();
 
 			// will be our iterator in the following loop
-			NoteVector::ConstIterator it = notes.begin();
+			auto it = notes.begin();
 
 			// loop through whole note-vector...
 			while( it != notes.end() )
@@ -3789,7 +3788,7 @@ void PianoRoll::wheelEvent(QWheelEvent * we )
 		{
 			if( i->withinRange( ticks_start, ticks_end ) || ( i->selected() && !altPressed ) )
 			{
-				nv += i;
+				nv.push_back(i);
 			}
 		}
 		if( nv.size() > 0 )
diff --git a/src/gui/editors/TrackContainerView.cpp b/src/gui/editors/TrackContainerView.cpp
index 38a6a36d5..83017fb1a 100644
--- a/src/gui/editors/TrackContainerView.cpp
+++ b/src/gui/editors/TrackContainerView.cpp
@@ -199,8 +199,8 @@ void TrackContainerView::moveTrackView( TrackView * trackView, int indexTo )
 
 	Track * track = m_tc->m_tracks[indexFrom];
 
-	m_tc->m_tracks.remove( indexFrom );
-	m_tc->m_tracks.insert( indexTo, track );
+	m_tc->m_tracks.erase(m_tc->m_tracks.begin() + indexFrom);
+	m_tc->m_tracks.insert(m_tc->m_tracks.begin() + indexTo, track);
 	m_trackViews.move( indexFrom, indexTo );
 
 	realignTracks();
diff --git a/src/gui/modals/ControllerConnectionDialog.cpp b/src/gui/modals/ControllerConnectionDialog.cpp
index 6396c7ccb..55c0b476f 100644
--- a/src/gui/modals/ControllerConnectionDialog.cpp
+++ b/src/gui/modals/ControllerConnectionDialog.cpp
@@ -258,10 +258,12 @@ ControllerConnectionDialog::ControllerConnectionDialog( QWidget * _parent,
 			}
 			else
 			{
-				int idx = Engine::getSong()->controllers().indexOf( cc->getController() );
+				auto& controllers = Engine::getSong()->controllers();
+				auto it = std::find(controllers.begin(), controllers.end(), cc->getController());
 
-				if( idx >= 0 )
+				if (it != controllers.end())
 				{
+					int idx = std::distance(it, controllers.begin());
 					m_userGroupBox->model()->setValue( true );
 					m_userController->model()->setValue( idx );
 				}
diff --git a/src/gui/tracks/TrackContentWidget.cpp b/src/gui/tracks/TrackContentWidget.cpp
index 26107c1ae..ca7123bda 100644
--- a/src/gui/tracks/TrackContentWidget.cpp
+++ b/src/gui/tracks/TrackContentWidget.cpp
@@ -345,7 +345,8 @@ bool TrackContentWidget::canPasteSelection( TimePos clipPos, const QMimeData* md
 
 	// Get the current track's index
 	const TrackContainer::TrackList tracks = t->trackContainer()->tracks();
-	const int currentTrackIndex = tracks.indexOf( t );
+	const auto currentTrackIt = std::find(tracks.begin(), tracks.end(), t);
+	const int currentTrackIndex = currentTrackIt != tracks.end() ? std::distance(tracks.begin(), currentTrackIt) : -1;
 
 	// Don't paste if we're on the same bar and allowSameBar is false
 	auto sourceTrackContainerId = metadata.attributeNode( "trackContainerId" ).value().toUInt();
@@ -443,7 +444,8 @@ bool TrackContentWidget::pasteSelection( TimePos clipPos, const QMimeData * md,
 
 	// Snap the mouse position to the beginning of the dropped bar, in ticks
 	const TrackContainer::TrackList tracks = getTrack()->trackContainer()->tracks();
-	const int currentTrackIndex = tracks.indexOf( getTrack() );
+	const auto currentTrackIt = std::find(tracks.begin(), tracks.end(), getTrack());
+	const int currentTrackIndex = currentTrackIt != tracks.end() ? std::distance(tracks.begin(), currentTrackIt) : -1;
 
 	bool wasSelection = m_trackView->trackContainerView()->rubberBand()->selectedObjects().count();
 
diff --git a/src/tracks/InstrumentTrack.cpp b/src/tracks/InstrumentTrack.cpp
index 7eb6bba11..1d2546288 100644
--- a/src/tracks/InstrumentTrack.cpp
+++ b/src/tracks/InstrumentTrack.cpp
@@ -739,7 +739,7 @@ bool InstrumentTrack::play( const TimePos & _start, const fpp_t _frames,
 		// get all notes from the given clip...
 		const NoteVector & notes = c->notes();
 		// ...and set our index to zero
-		NoteVector::ConstIterator nit = notes.begin();
+		auto nit = notes.begin();
 
 		// very effective algorithm for playing notes that are
 		// posated within the current sample-frame
diff --git a/src/tracks/MidiClip.cpp b/src/tracks/MidiClip.cpp
index 08e76ae59..52a532028 100644
--- a/src/tracks/MidiClip.cpp
+++ b/src/tracks/MidiClip.cpp
@@ -115,11 +115,11 @@ void MidiClip::resizeToFirstTrack()
 		{
 			if (track != m_instrumentTrack)
 			{
-				unsigned int currentClip = m_instrumentTrack->
-					getClips().indexOf(this);
-				m_steps = static_cast<MidiClip *>
-					(track->getClip(currentClip))
-					->m_steps;
+				const auto& instrumentTrackClips = m_instrumentTrack->getClips();
+				const auto currentClipIt = std::find(instrumentTrackClips.begin(), instrumentTrackClips.end(), this);
+				unsigned int currentClip = currentClipIt != instrumentTrackClips.end() ?
+					std::distance(instrumentTrackClips.begin(), currentClipIt) : -1;
+				m_steps = static_cast<MidiClip*>(track->getClip(currentClip))->m_steps;
 			}
 			break;
 		}
@@ -218,17 +218,14 @@ Note * MidiClip::addNote( const Note & _new_note, const bool _quant_pos )
 void MidiClip::removeNote( Note * _note_to_del )
 {
 	instrumentTrack()->lock();
-	NoteVector::Iterator it = m_notes.begin();
-	while( it != m_notes.end() )
+
+	m_notes.erase(std::remove_if(m_notes.begin(), m_notes.end(), [&](Note* note)
 	{
-		if( *it == _note_to_del )
-		{
-			delete *it;
-			m_notes.erase( it );
-			break;
-		}
-		++it;
-	}
+		auto shouldRemove = note == _note_to_del;
+		if (shouldRemove) { delete note; }
+		return shouldRemove;
+	}), m_notes.end());
+
 	instrumentTrack()->unlock();
 
 	checkType();
@@ -354,15 +351,13 @@ void MidiClip::setType( MidiClipTypes _new_clip_type )
 
 void MidiClip::checkType()
 {
-	NoteVector::Iterator it = m_notes.begin();
-	while( it != m_notes.end() )
+	for (auto& note : m_notes)
 	{
-		if( ( *it )->length() > 0 )
+		if (note->length() > 0)
 		{
-			setType( MelodyClip );
+			setType(MelodyClip);
 			return;
 		}
-		++it;
 	}
 	setType( BeatClip );
 }
@@ -395,9 +390,9 @@ void MidiClip::saveSettings( QDomDocument & _doc, QDomElement & _this )
 	_this.setAttribute( "steps", m_steps );
 
 	// now save settings of all notes
-	for (const auto& note : m_notes)
+	for (auto& note : m_notes)
 	{
-		note->saveState( _doc, _this );
+		note->saveState(_doc, _this);
 	}
 }
 
@@ -477,9 +472,10 @@ MidiClip *  MidiClip::nextMidiClip() const
 
 MidiClip * MidiClip::adjacentMidiClipByOffset(int offset) const
 {
-	QVector<Clip *> clips = m_instrumentTrack->getClips();
+	std::vector<Clip *> clips = m_instrumentTrack->getClips();
 	int clipNum = m_instrumentTrack->getClipNum(this);
-	return dynamic_cast<MidiClip*>(clips.value(clipNum + offset, nullptr));
+	if (clipNum < 0 || clipNum > clips.size() - 1) { return nullptr; }
+	return dynamic_cast<MidiClip*>(clips[clipNum + offset]);
 }