Customizer: Ensure persistence of unchanged `active` state for controls, sections, and panels.

Cherry-picks [33754] onto 4.3 branch.
Props nikeo, westonruter.
Fixes #33428 for 4.3.
See also #33494.

Built from https://develop.svn.wordpress.org/branches/4.3@33941


git-svn-id: http://core.svn.wordpress.org/branches/4.3@33910 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/customize-controls.js

@@ -286,8 +286,15 @@
 		 * @param {Object}  args.duration
 		 * @param {Object}  args.completeCallback
 		 */
-		onChangeActive: function ( active, args ) {
+		onChangeActive: function( active, args ) {
 			var duration, construct = this;
+			if ( args.unchanged ) {
+				if ( args.completeCallback ) {
+					args.completeCallback();
+				}
+				return;
+			}
+
 			duration = ( 'resolved' === api.previewer.deferred.active.state() ? args.duration : 0 );
 			if ( ! $.contains( document, construct.container[0] ) ) {
 				// jQuery.fn.slideUp is not hiding an element if it is not in the DOM
@@ -1499,6 +1506,13 @@
 		 * @param {Callback} args.completeCallback
 		 */
 		onChangeActive: function ( active, args ) {
+			if ( args.unchanged ) {
+				if ( args.completeCallback ) {
+					args.completeCallback();
+				}
+				return;
+			}
+
 			if ( ! $.contains( document, this.container ) ) {
 				// jQuery.fn.slideUp is not hiding an element if it is not in the DOM
 				this.container.toggle( active );