diff --git a/js/Checkbox.js b/js/Checkbox.js
index 35fdb952..bd340d87 100644
--- a/js/Checkbox.js
+++ b/js/Checkbox.js
@@ -49,6 +49,7 @@ define( function( require ) {
       phetioEventType: 'user',
       phetioReadOnly: PhetioObject.DEFAULT_OPTIONS.phetioReadOnly, // to support properly passing this to children, see https://github.com/phetsims/tandem/issues/60
       phetioDocumentation: '', // different default than PhetioObject, see implementation below
+      phetioControlledProperty: property,
 
       // a11y
       tagName: 'input',
@@ -90,13 +91,6 @@ define( function( require ) {
       phetioDocumentation: 'When disabled, the checkbox is grayed out and cannot be pressed.'
     } );
 
-    // (phet-io) document the instrumented Property that this Checkbox manipulates
-    options.phetioDocumentation +=
-      ' This checkbox controls the PropertyIO.<BooleanIO>: ' +
-      '<a href="#' + phetio.PhetioIDUtils.getDOMElementID( property.tandem.phetioID ) + '">' + property.tandem.phetioID + '</a>';
-    options.phetioDocumentation = options.phetioDocumentation.trim(); // eliminate preceding whitespace, if any.
-
-
     // @private - sends out notifications when the checkbox is toggled.
     var toggledEmitter = new Emitter( {
       tandem: options.tandem.createTandem( 'toggledEmitter' ),
@@ -181,10 +175,6 @@ define( function( require ) {
 
     // assert that phet-io is set up correctly after the PhetioObject has been properly initialized (after mutate)
 
-    // If either one is instrumented, then the other must be too.
-    assert && Tandem.validationEnabled() && assert( this.isPhetioInstrumented() === property.isPhetioInstrumented(),
-      'Property must be instrumented if controlling Checkbox is.' );
-
     // If either one is instrumented, then the other must be too.
     assert && Tandem.validationEnabled() && assert( this.enabledProperty.isPhetioInstrumented() === this.isPhetioInstrumented(), 'provided enabled property must be instrumented for phet-io.' );
 
diff --git a/js/ComboBox.js b/js/ComboBox.js
index 24697dac..8bd8ea7b 100644
--- a/js/ComboBox.js
+++ b/js/ComboBox.js
@@ -74,6 +74,8 @@ define( require => {
       tandem: Tandem.required,
       phetioType: ComboBoxIO,
       phetioEventType: 'user',
+      phetioDocumentation: '', // different default than PhetioObject, see implementation below
+      phetioControlledProperty: property,
 
       // a11y
       a11yButtonLabel: '' // {string} accessible label for the button that opens this combobox
@@ -273,7 +275,7 @@ define( require => {
     this.buttonNode = new ButtonNode( new ComboBoxItemNode( items[ 0 ], itemWidth, itemHeight, options.itemXMargin ), options );
     this.addChild( this.buttonNode );
 
-    // a11y - the list is labelledby the button's label
+    // a11y - the list is labeled by the button's label
     this.listNode.addAriaLabelledbyAssociation( {
       otherNode: this.buttonNode,
       otherElementName: AccessiblePeer.LABEL_SIBLING,