From 2585e81d103b324a74b694a5cdc51278d8f230cf Mon Sep 17 00:00:00 2001
From: samreid <reids@colorado.edu>
Date: Mon, 26 Nov 2018 10:27:06 -0700
Subject: [PATCH] Added "This exists for the lifetime of the sim and doesn't
 require disposal." where appropriate, see
 https://github.com/phetsims/wave-interference/issues/191

---
 js/common/view/LatticeCanvasNode.js            |  2 +-
 js/common/view/LightEmitterNode.js             |  7 +++++--
 js/common/view/SceneToggleNode.js              |  3 ++-
 js/common/view/SoundParticleDevPanel.js        | 15 +++++++++++++--
 js/common/view/TimeControlPanel.js             |  4 +++-
 js/common/view/WaterEmitterNode.js             |  1 +
 js/common/view/WaveAreaGraphNode.js            |  3 ++-
 js/common/view/WaveInterferenceControlPanel.js | 11 ++++++++++-
 js/common/view/WaveInterferenceSceneIcons.js   |  2 ++
 js/common/view/WaveInterferenceSlider.js       |  3 ++-
 js/common/view/WaveMeterNode.js                |  8 +++++++-
 js/diffraction/view/DiffractionScreenView.js   | 16 ++++++++++++++++
 js/interference/view/InterferenceScreenView.js |  8 ++++++++
 js/slits/view/BarriersNode.js                  |  1 +
 js/slits/view/SlitsControlPanel.js             | 17 +++++++++++++++++
 js/slits/view/SlitsScreenView.js               |  3 +++
 js/waves/view/WavesScreenView.js               |  7 +++++++
 17 files changed, 100 insertions(+), 11 deletions(-)

diff --git a/js/common/view/LatticeCanvasNode.js b/js/common/view/LatticeCanvasNode.js
index 2d519a01..eb71d62b 100644
--- a/js/common/view/LatticeCanvasNode.js
+++ b/js/common/view/LatticeCanvasNode.js
@@ -71,7 +71,7 @@ define( require => {
      * @param {Vector2} point - point in the local coordinate frame
      * @returns {Vector2}
      */
-    localPointToLatticePoint( point ) {
+    static localPointToLatticePoint( point ) {
       return new Vector2( Math.floor( point.x / CELL_WIDTH ), Math.floor( point.y / CELL_WIDTH ) );
     }
 
diff --git a/js/common/view/LightEmitterNode.js b/js/common/view/LightEmitterNode.js
index 9646918c..28460beb 100644
--- a/js/common/view/LightEmitterNode.js
+++ b/js/common/view/LightEmitterNode.js
@@ -31,9 +31,12 @@ define( require => {
      */
     constructor( model, waveAreaNode, isPrimarySource ) {
       let scene = model.lightScene;
-      super( model, scene, waveAreaNode, 70, isPrimarySource, new LaserPointerNode( scene.button1PressedProperty, _.extend( {
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
+      const laserPointerNode = new LaserPointerNode( scene.button1PressedProperty, _.extend( {
         rightCenter: waveAreaNode.leftCenter.plusXY( 20, 0 )
-      }, DEFAULTS ) ) );
+      }, DEFAULTS ) );
+      super( model, scene, waveAreaNode, 70, isPrimarySource, laserPointerNode );
     }
 
     /**
diff --git a/js/common/view/SceneToggleNode.js b/js/common/view/SceneToggleNode.js
index 1d063aac..a2df4fc0 100644
--- a/js/common/view/SceneToggleNode.js
+++ b/js/common/view/SceneToggleNode.js
@@ -1,7 +1,8 @@
 // Copyright 2018, University of Colorado Boulder
 
 /**
- * A ToggleNode that shows something different for each scene.
+ * A ToggleNode that shows something different for each scene.  All SceneToggleNodes in this sim exist for the lifetime
+ * of the sim and doesn't require disposal.
  *
  * @author Sam Reid (PhET Interactive Simulations)
  */
diff --git a/js/common/view/SoundParticleDevPanel.js b/js/common/view/SoundParticleDevPanel.js
index 4d470866..f44e330a 100644
--- a/js/common/view/SoundParticleDevPanel.js
+++ b/js/common/view/SoundParticleDevPanel.js
@@ -28,25 +28,36 @@ define( require => {
         children: [
 
           // TODO: delete or keep?  Fine tuning and discussion in https://github.com/phetsims/wave-interference/issues/142
+          // This exists for the lifetime of the sim and doesn't require disposal.
           new NumberControl( 'cutoff',
             WaveInterferenceConstants.CUTOFF,
             new Range( 0, 1 ),
             _.extend( { delta: 0.01, decimalPlaces: 2 }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS )
           ),
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
           new NumberControl( 'randomness',
             WaveInterferenceConstants.SOUND_PARTICLE_RANDOMNESS_PROPERTY,
             new Range( 0, 30 ),
             _.extend( { delta: 0.25, decimalPlaces: 2 }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS )
           ),
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
           new NumberControl( 'ADJUST home force',
             WaveInterferenceConstants.SOUND_PARTICLE_RESTORATION_SCALE,
             new Range( 0.1, 2 ),
             _.extend( { delta: 0.01, decimalPlaces: 2 }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS )
-          ), new NumberControl( 'friction (1=none)',
+          ),
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
+          new NumberControl( 'friction (1=none)',
             WaveInterferenceConstants.SOUND_PARTICLE_FRICTION_SCALE_PROPERTY,
             new Range( 0.7, 1.0 ),
             _.extend( { delta: 0.005, decimalPlaces: 3 }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS )
-          ), new NumberControl( 'ADJUST gradient force',
+          ),
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
+          new NumberControl( 'ADJUST gradient force',
             WaveInterferenceConstants.SOUND_PARTICLE_GRADIENT_FORCE_SCALE_PROPERTY,
             new Range( 0.1, 2 ),
             _.extend( { delta: 0.01, decimalPlaces: 2 }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS )
diff --git a/js/common/view/TimeControlPanel.js b/js/common/view/TimeControlPanel.js
index 11d7a97e..a4607346 100644
--- a/js/common/view/TimeControlPanel.js
+++ b/js/common/view/TimeControlPanel.js
@@ -33,10 +33,12 @@ define( require => {
      */
     constructor( model, options ) {
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const playPauseButton = new PlayPauseButton( model.isRunningProperty, {
         scale: BUTTON_SCALE
       } );
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const radioButtonGroup = new WaveInterferenceVerticalAquaRadioButtonGroup( [ {
         node: new WaveInterferenceText( normalString ),
         value: PlaySpeedEnum.NORMAL,
@@ -48,7 +50,7 @@ define( require => {
       } ] );
 
       const stepButton = new StepButton( {
-        scale: BUTTON_SCALE
+        scale: BUTTON_SCALE // TODO: can listener be inlined?
       } );
 
       // If we need to move forward further than one frame, call advanceTime several times rather than increasing the
diff --git a/js/common/view/WaterEmitterNode.js b/js/common/view/WaterEmitterNode.js
index 9a585447..7641f15f 100644
--- a/js/common/view/WaterEmitterNode.js
+++ b/js/common/view/WaterEmitterNode.js
@@ -29,6 +29,7 @@ define( require => {
      */
     constructor( model, waveAreaNode, isPrimarySource ) {
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const faucetNode = new FaucetNode(
         // This value is irrelevant because we use our own faucet water emitting model, but must be nonzero
         // to prevent a divide by zero problem
diff --git a/js/common/view/WaveAreaGraphNode.js b/js/common/view/WaveAreaGraphNode.js
index 213d3e73..414517b4 100644
--- a/js/common/view/WaveAreaGraphNode.js
+++ b/js/common/view/WaveAreaGraphNode.js
@@ -50,7 +50,7 @@ define( require => {
       // the bottom tab will fit the largest label.
       const horizontalAxisLabel = new SceneToggleNode( model, scene => new WaveInterferenceText( scene.graphHorizontalAxisLabel ) );
 
-      // Scene-specific title of the chart
+      // Scene-specific title of the chart.
       const title = new SceneToggleNode( model, scene => new WaveInterferenceText( scene.graphTitle ) );
 
       const HORIZONTAL_LABEL_VERTICAL_MARGIN = 2;
@@ -85,6 +85,7 @@ define( require => {
       );
       const lastTickLabel = horizontalAxisTickLabels[ horizontalAxisTickLabels.length - 1 ];
       const tickBubbleXMargin = 2;
+
       const verticalAxisLabel = new SceneToggleNode( model, scene => new WaveInterferenceText( scene.verticalAxisTitle ), {
         rotation: 3 * Math.PI / 2,
         right: -TEXT_MARGIN_Y,
diff --git a/js/common/view/WaveInterferenceControlPanel.js b/js/common/view/WaveInterferenceControlPanel.js
index 27400979..137f2d02 100644
--- a/js/common/view/WaveInterferenceControlPanel.js
+++ b/js/common/view/WaveInterferenceControlPanel.js
@@ -95,13 +95,15 @@ define( require => {
 
       lightFrequencySlider.centerTop = soundFrequencySlider.centerTop.plusXY( 0, 10 );
       const frequencySliderContainer = new Node( { children: [ waterFrequencySlider, soundFrequencySlider, lightFrequencySlider ] } );
+
       const amplitudeSliderContainer = new SceneToggleNode( model, scene => {
 
         // For water scene, control the desiredAmplitude (which determines the size of the water drops)
-        // For other scenes, control the amplitude directly.
+        // For other scenes, control the amplitude directly. This exists for the lifetime of the sim and doesn't require disposal.
         return new WaveInterferenceSlider( scene.desiredAmplitudeProperty || scene.amplitudeProperty, scene.amplitudeProperty.range.min, scene.amplitudeProperty.range.max );
       } );
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const viewSelectionRadioButtonGroup = new VerticalAquaRadioButtonGroup( [ {
         node: new WaveInterferenceText( wavesString ),
         value: SoundViewType.WAVES,
@@ -121,9 +123,14 @@ define( require => {
           radius: 6.5
         }
       } );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const graphCheckbox = new Checkbox( new WaveInterferenceText( graphString ), model.showGraphProperty, CHECKBOX_OPTIONS );
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const screenCheckbox = new Checkbox( new WaveInterferenceText( screenString ), model.showScreenProperty, CHECKBOX_OPTIONS );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const intensityCheckbox = new Checkbox( new WaveInterferenceText( intensityString ), model.showIntensityGraphProperty, CHECKBOX_OPTIONS );
 
       // Only enable the intensity checkbox when the screen is selected
@@ -141,6 +148,8 @@ define( require => {
 
       // Create faucet icon, and rasterize to clip out invisible parts (like the ShooterNode)
       const sceneIcons = new WaveInterferenceSceneIcons();
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const sceneRadioButtons = new RadioButtonGroup( model.sceneProperty, [
         { value: model.waterScene, node: sceneIcons.faucetIcon },
         { value: model.soundScene, node: sceneIcons.speakerIcon },
diff --git a/js/common/view/WaveInterferenceSceneIcons.js b/js/common/view/WaveInterferenceSceneIcons.js
index e0bd8020..103600ed 100644
--- a/js/common/view/WaveInterferenceSceneIcons.js
+++ b/js/common/view/WaveInterferenceSceneIcons.js
@@ -22,6 +22,7 @@ define( require => {
     constructor() {
 
       // @public - Faucet icon, and rasterize to clip out invisible parts (like the ShooterNode)
+      // This exists for the lifetime of the sim and doesn't require disposal.
       this.faucetIcon = new FaucetNode( 1, new Property( 0 ), new Property( true ), {
         interactiveProperty: new Property( false )
       } ).rasterized();
@@ -30,6 +31,7 @@ define( require => {
       this.speakerIcon = new Image( speakerImage );
 
       // @public - Laser Pointer icon
+      // This exists for the lifetime of the sim and doesn't require disposal.
       this.laserPointerIcon = new LaserPointerNode( new BooleanProperty( false ), LightEmitterNode.DEFAULT_OPTIONS );
 
       // Uniform sizing.
diff --git a/js/common/view/WaveInterferenceSlider.js b/js/common/view/WaveInterferenceSlider.js
index 3f7d6c8a..6503e1ba 100644
--- a/js/common/view/WaveInterferenceSlider.js
+++ b/js/common/view/WaveInterferenceSlider.js
@@ -1,7 +1,8 @@
 // Copyright 2018, University of Colorado Boulder
 
 /**
- * Slider abstraction for the frequency and amplitude sliders.
+ * Slider abstraction for the frequency and amplitude sliders.  All instances exist for the lifetime of the sim
+ * and do not require disposal.
  *
  * @author Sam Reid (PhET Interactive Simulations)
  */
diff --git a/js/common/view/WaveMeterNode.js b/js/common/view/WaveMeterNode.js
index 5fca4d6d..e46bfadf 100644
--- a/js/common/view/WaveMeterNode.js
+++ b/js/common/view/WaveMeterNode.js
@@ -114,6 +114,7 @@ define( require => {
         model.rotationAmountProperty.link( snapToCenter );
 
         // Add the wire behind the probe.
+        // This exists for the lifetime of the sim and doesn't require disposal.
         this.addChild( new WireNode( connectionProperty, new Property( new Vector2( -NORMAL_DISTANCE, 0 ) ),
           new NodeProperty( probeNode, 'bounds', 'centerBottom' ), new Property( new Vector2( 0, NORMAL_DISTANCE ) ), {
             lineWidth: WIRE_LINE_WIDTH,
@@ -127,7 +128,7 @@ define( require => {
         this.on( 'visibility', alignProbes );
         this.alignProbesEmitter.addListener( alignProbes );
 
-        const dynamicSeries = new DynamicSeries( { color } );
+        const dynamicSeries = new DynamicSeries( { color: color } );
         dynamicSeries.probeNode = probeNode;
 
         const updateSamples = function() {
@@ -176,7 +177,10 @@ define( require => {
         return dynamicSeries;
       };
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const aboveBottomLeft1 = new DerivedProperty( [ leftBottomProperty ], position => position.isFinite() ? position.plusXY( 0, -20 ) : Vector2.ZERO );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const aboveBottomLeft2 = new DerivedProperty( [ leftBottomProperty ], position => position.isFinite() ? position.plusXY( 0, -10 ) : Vector2.ZERO );
       const series1 = initializeSeries( SERIES_1_COLOR, WIRE_1_COLOR, 5, 10, aboveBottomLeft1 );
       const series2 = initializeSeries( SERIES_2_COLOR, WIRE_2_COLOR, 36, 54, aboveBottomLeft2 );
@@ -198,7 +202,9 @@ define( require => {
       const timeProperty = new DynamicProperty( model.sceneProperty, {
         derive: 'timeProperty'
       } );
+
       const scrollingChartNode = new LabeledScrollingChartNode(
+        // This exists for the lifetime of the sim and doesn't require disposal.
         new ScrollingChartNode( timeProperty, [ series1, series2 ], {
           width: 150,
           height: 110
diff --git a/js/diffraction/view/DiffractionScreenView.js b/js/diffraction/view/DiffractionScreenView.js
index 1a29b730..fb5aeee8 100644
--- a/js/diffraction/view/DiffractionScreenView.js
+++ b/js/diffraction/view/DiffractionScreenView.js
@@ -50,6 +50,8 @@ define( require => {
 
       // @private
       this.model = model;
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const laserPointerNode = new LaserPointerNode( model.onProperty, {
         left: 10,
         centerY: 50,
@@ -72,6 +74,8 @@ define( require => {
         value: 'circle',
         node: new Circle( 10, { fill: 'black' } )
       } ];
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const radioButtonGroup = new RadioButtonGroup( model.sceneProperty, toggleButtonsContent, {
         left: 10,
         bottom: this.layoutBounds.bottom - 10
@@ -129,9 +133,13 @@ define( require => {
       this.squareControlPanel = new Panel( new VBox( {
         spacing: BOX_SPACING,
         children: [
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
           new NumberControl( 'width', model.squareWidthProperty, new Range( 2, 30 ), _.extend( {
             delta: 2 // avoid odd/even artifacts
           }, NUMBER_CONTROL_OPTIONS ) ),
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
           new NumberControl( 'height', model.squareHeightProperty, new Range( 2, 30 ), _.extend( {
             delta: 2 // avoid odd/even artifacts
           }, NUMBER_CONTROL_OPTIONS ) ) ]
@@ -143,7 +151,11 @@ define( require => {
       this.gaussianControlPanel = new Panel( new VBox( {
         spacing: BOX_SPACING,
         children: [
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
           new NumberControl( 'sigmaX', model.sigmaXProperty, new Range( 2, 10 ), NUMBER_CONTROL_OPTIONS ),
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
           new NumberControl( 'sigmaY', model.sigmaYProperty, new Range( 2, 10 ), NUMBER_CONTROL_OPTIONS )
         ]
       } ), _.extend( {
@@ -154,7 +166,11 @@ define( require => {
       this.slitsControlPanel = new Panel( new VBox( {
         spacing: BOX_SPACING,
         children: [
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
           new NumberControl( 'number of lines', model.numberOfLinesProperty, new Range( 2, 200 ), NUMBER_CONTROL_OPTIONS ),
+
+          // This exists for the lifetime of the sim and doesn't require disposal.
           new NumberControl( 'angle', model.angleProperty, new Range( 0, Math.PI * 2 ), _.extend( {
             delta: 0.01
           }, NUMBER_CONTROL_OPTIONS ) )
diff --git a/js/interference/view/InterferenceScreenView.js b/js/interference/view/InterferenceScreenView.js
index 7d3b94e8..62221cec 100644
--- a/js/interference/view/InterferenceScreenView.js
+++ b/js/interference/view/InterferenceScreenView.js
@@ -33,8 +33,12 @@ define( require => {
 
       const createLabelText = string => new WaveInterferenceText( string, { fontSize: 10 } );
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
+      // TODO: use SceneToggleNode?
       const toggleNode = new ToggleNode( model.sceneProperty, [ {
         value: model.waterScene,
+
+        // This exists for the lifetime of the sim and doesn't require disposal.
         node: new NumberControl( separationString, model.waterScene.desiredSourceSeparationProperty, new Range( 1, 5 ), _.extend( {
           delta: 1,
           valuePattern: cmValueString,
@@ -45,6 +49,8 @@ define( require => {
         }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS ) )
       }, {
         value: model.soundScene,
+
+        // This exists for the lifetime of the sim and doesn't require disposal.
         node: new NumberControl( separationString, model.soundScene.sourceSeparationProperty, new Range( 100, 200 ), _.extend( {
           delta: 5,
           valuePattern: cmValueString,
@@ -54,6 +60,8 @@ define( require => {
         }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS ) )
       }, {
         value: model.lightScene,
+
+        // This exists for the lifetime of the sim and doesn't require disposal.
         node: new NumberControl( separationString, model.lightScene.sourceSeparationProperty, new Range( 500, 2500 ), _.extend( {
           delta: 500,
           valuePattern: nmValueString,
diff --git a/js/slits/view/BarriersNode.js b/js/slits/view/BarriersNode.js
index 025d29e6..cb0a2e1a 100644
--- a/js/slits/view/BarriersNode.js
+++ b/js/slits/view/BarriersNode.js
@@ -69,6 +69,7 @@ define( require => {
       // @private - Convert from model coordinates to view coordinates
       this.modelViewTransform = ModelViewTransform2.createRectangleMapping( this.scene.getWaveAreaBounds(), viewBounds );
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       this.addInputListener( new DragListener( {
         locationProperty: scene.barrierLocationProperty,
         transform: this.modelViewTransform,
diff --git a/js/slits/view/SlitsControlPanel.js b/js/slits/view/SlitsControlPanel.js
index 2ecf7cba..4ce53000 100644
--- a/js/slits/view/SlitsControlPanel.js
+++ b/js/slits/view/SlitsControlPanel.js
@@ -44,6 +44,8 @@ define( require => {
         derive: 'barrierTypeProperty',
         bidirectional: true
       } );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const comboBox = new ComboBox( [
         ComboBox.createItem( new WaveInterferenceText( noBarrierString ), BarrierTypeEnum.NO_BARRIER ),
         ComboBox.createItem( new WaveInterferenceText( oneSlitString ), BarrierTypeEnum.ONE_SLIT ),
@@ -60,22 +62,30 @@ define( require => {
       ];
 
       const waterRange = new Range( 0, 5 );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const waterSlitWidthControl = new NumberControl( slitWidthString, model.waterScene.slitWidthProperty, waterRange, _.extend( {
         valuePattern: cmValueString,
         majorTicks: createTicks( waterRange )
       }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS ) );
 
       const soundRange = new Range( 0, 100 );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const soundSlitWidthControl = new NumberControl( slitWidthString, model.soundScene.slitWidthProperty, soundRange, _.extend( {
         valuePattern: cmValueString,
         majorTicks: createTicks( soundRange )
       }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS ) );
 
       const lightRange = new Range( 0, 2000 );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const lightSlitWidthControl = new NumberControl( slitWidthString, model.lightScene.slitWidthProperty, lightRange, _.extend( {
         valuePattern: nmValueString,
         majorTicks: createTicks( lightRange )
       }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS ) );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const slitWidthControl = new ToggleNode( model.sceneProperty, [
         { value: model.waterScene, node: waterSlitWidthControl },
         { value: model.soundScene, node: soundSlitWidthControl },
@@ -89,23 +99,30 @@ define( require => {
       } );
 
       const waterSeparationRange = new Range( 0, 5 );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const waterSeparationControl = new NumberControl( slitSeparationString, model.waterScene.slitSeparationProperty, waterSeparationRange, _.extend( {
         valuePattern: cmValueString,
         majorTicks: createTicks( waterSeparationRange )
       }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS ) );
 
       const soundSeparationRange = new Range( 0, 200 );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const soundSeparationControl = new NumberControl( slitSeparationString, model.soundScene.slitSeparationProperty, soundSeparationRange, _.extend( {
         valuePattern: cmValueString,
         majorTicks: createTicks( soundSeparationRange )
       }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS ) );
 
       const lightSeparationRange = new Range( 0, 2000 );
+
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const lightSeparationControl = new NumberControl( slitSeparationString, model.lightScene.slitSeparationProperty, lightSeparationRange, _.extend( {
         valuePattern: nmValueString,
         majorTicks: createTicks( lightSeparationRange )
       }, WaveInterferenceConstants.NUMBER_CONTROL_OPTIONS ) );
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const slitSeparationControl = new ToggleNode( model.sceneProperty, [
         { value: model.waterScene, node: waterSeparationControl },
         { value: model.soundScene, node: soundSeparationControl },
diff --git a/js/slits/view/SlitsScreenView.js b/js/slits/view/SlitsScreenView.js
index 33439356..e4ab2a40 100644
--- a/js/slits/view/SlitsScreenView.js
+++ b/js/slits/view/SlitsScreenView.js
@@ -36,6 +36,7 @@ define( require => {
       } );
 
       // The Slits screen has an additional control panel below the main control panel, which controls the barrier/slits
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const slitControlPanel = new SlitsControlPanel( alignGroup, model, this );
 
       // When the alignGroup changes the size of the slitsControlPanel, readjust its positioning.  Should only happen
@@ -69,6 +70,8 @@ define( require => {
 
       // When enabled by a query parameter, show the theoretical interference pattern.
       if ( WaveInterferenceQueryParameters.theory ) {
+
+        // This exists for the lifetime of the sim and doesn't require disposal.
         this.addChild( new TheoryInterferenceOverlay( model, this.waveAreaNode.bounds, {
           clipArea: Shape.bounds( this.waveAreaNode.bounds )
         } ) );
diff --git a/js/waves/view/WavesScreenView.js b/js/waves/view/WavesScreenView.js
index 355c12de..726ca626 100644
--- a/js/waves/view/WavesScreenView.js
+++ b/js/waves/view/WavesScreenView.js
@@ -216,6 +216,7 @@ define( require => {
        */
       const toolboxContains = point => toolboxPanel.parentToGlobalBounds( toolboxPanel.bounds ).containsPoint( point );
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const measuringTapeNode = new MeasuringTapeNode( measuringTapeProperty, new BooleanProperty( true ), {
 
         // translucent white background, same value as in Projectile Motion, see https://github.com/phetsims/projectile-motion/issues/156
@@ -233,6 +234,7 @@ define( require => {
       } );
       model.isMeasuringTapeInPlayAreaProperty.linkAttribute( measuringTapeNode, 'visible' );
 
+      // This exists for the lifetime of the sim and doesn't require disposal.
       const timerNode = new WaveInterferenceTimerNode( model, {
 
         // Drop in toolbox
@@ -309,6 +311,7 @@ define( require => {
       this.addChild( this.controlPanel );
 
       if ( options.showPulseContinuousRadioButtons ) {
+
         this.addChild( new SceneToggleNode( model, scene => new PulseContinuousRadioButtonGroup( scene.waveTemporalTypeProperty ), {
           bottom: this.layoutBounds.bottom - MARGIN,
           left: this.layoutBounds.left + MARGIN
@@ -316,6 +319,8 @@ define( require => {
       }
 
       if ( options.showViewRadioButtonGroup ) {
+
+        // This exists for the lifetime of the sim and doesn't require disposal.
         this.addChild( new ViewRadioButtonGroup( model.viewTypeProperty, {
           bottom: this.layoutBounds.bottom - MARGIN,
           left: this.waveAreaNode.left + SPACING + 10
@@ -400,6 +405,8 @@ define( require => {
 
       /**
        * Creates a ToggleNode that shows the primary or secondary source
+       * This exists for the lifetime of the sim and doesn't require disposal.
+       * TODO: use SceneToggleNode?
        * @param {boolean} isPrimarySource - true if it should show the primary source
        */
       const createEmitterToggleNode = isPrimarySource => new ToggleNode( model.sceneProperty, [