Index: tests/qunit/fixtures/customize-settings.js
===================================================================
--- tests/qunit/fixtures/customize-settings.js	(revision 39146)
+++ tests/qunit/fixtures/customize-settings.js	(working copy)
@@ -3,7 +3,15 @@
 
 var customizerRootElement;
 customizerRootElement = jQuery( '<div id="customize-theme-controls"><ul></ul></div>' );
-customizerRootElement.css( { position: 'absolute', left: -10000, top: -10000 } ); // Remove from view.
+// Remove from view.
+customizerRootElement.css({
+	height: "1px",
+	left: "-10px",
+	overflow: "hidden",
+	position: "absolute",
+	top: "-10px",
+	width: "1px",
+});
 jQuery( document.body ).append( customizerRootElement );
 
 window._wpCustomizeSettings = {
Index: tests/qunit/wp-admin/js/customize-base.js
===================================================================
--- tests/qunit/wp-admin/js/customize-base.js	(revision 39146)
+++ tests/qunit/wp-admin/js/customize-base.js	(working copy)
@@ -4,6 +4,15 @@
 	var FooSuperClass, BarSubClass, foo, bar, ConstructorTestClass, newConstructor, constructorTest, $mockElement, mockString,
 	firstInitialValue, firstValueInstance, wasCallbackFired, mockValueCallback;
 
+	QUnit.done( function() {
+		// Clean up.
+		[ 'panel', 'section', 'control' ].forEach(function ( type ) {
+			wp.customize[ type ].each(function ( instance ) {
+				instance.container.remove();
+			});
+		});
+	});
+
 	module( 'Customize Base: Class' );
 
 	FooSuperClass = wp.customize.Class.extend(
Index: tests/qunit/wp-admin/js/customize-controls.js
===================================================================
--- tests/qunit/wp-admin/js/customize-controls.js	(revision 39146)
+++ tests/qunit/wp-admin/js/customize-controls.js	(working copy)
@@ -545,6 +545,9 @@
 
 	test( 'Panel instance is not contextuallyActive', function () {
 		equal( mockPanel.isContextuallyActive(), false );
+
+		// Clean up.
+		mockPanel.container.remove();
 	});
 
 	module( 'Test wp.customize.findControlsForSettings' );