diff --git a/js/ComboBox.js b/js/ComboBox.js
index 05c11361..8a025352 100644
--- a/js/ComboBox.js
+++ b/js/ComboBox.js
@@ -50,13 +50,13 @@ define( require => {
       labelXSpacing: 10, // horizontal space between label and combo box
       enabledProperty: new Property( true ),
       disabledOpacity: 0.5, // {number} opacity used to make the control look disabled
-      cornerRadius: 8, // {number} applied to list and button
+      cornerRadius: 4, // {number} applied to list and button
       highlightFill: 'rgb( 245, 245, 245 )', // highlight behind items in the list
 
       // Margins around the edges of the list when highlight is invisible.
       // Highlight margins around the items in the list are set to 1/2 of these values.
       xMargin: 12,
-      yMargin: 8,
+      yMargin: 6,
 
       // button
       buttonFill: 'white',
diff --git a/js/ComboBoxButton.js b/js/ComboBoxButton.js
index 9e848c0d..611e2f68 100644
--- a/js/ComboBoxButton.js
+++ b/js/ComboBoxButton.js
@@ -45,11 +45,10 @@ define( require => {
         cursor: 'pointer',
         baseColor: 'white',
         buttonAppearanceStrategy: RectangularButtonView.FlatAppearanceStrategy,
-        xMargin: 10, // margin on the left and right of the item
-        yMargin: 10, // margin on the top and bottom of the item
+        xMargin: 12,
+        yMargin: 6,
         stroke: 'black',
         lineWidth: 1,
-        cornerRadius: 8,
 
         // phet-io
         tandem: Tandem.optional,