Index: src/wp-admin/css/customize-controls.css
===================================================================
--- src/wp-admin/css/customize-controls.css	(revision 31634)
+++ src/wp-admin/css/customize-controls.css	(working copy)
@@ -852,6 +852,77 @@
 	display: block;
 }
 
+.customize-themes-panel .customize-info {
+	padding: 12px 7px 15px;
+}
+
+.customize-themes-panel .customize-info .preview-action {
+	font-size: 13px;
+	line-height: 24px;
+	display: block;
+}
+
+.customize-themes-panel .customize-info .panel-title {
+	font-size: 20px;
+	font-weight: 200;
+	line-height: 24px;
+}
+
+.customize-themes-panel .customize-info .title-count {
+	top: -1px;
+	padding: 2px 8px;
+}
+
+.customize-themes-panel .customize-info .button {
+	float: right;
+	margin-top: -2px;
+	position: relative;
+}
+
+.customize-themes-panel .customize-section-title {
+	background: #fff;
+	color: #222;
+	padding: 10px 10px 11px 14px;
+	line-height: 21px;
+	cursor: pointer;
+	margin: 0 -8px 12px -8px;
+}
+
+.customize-section-title .action,
+.accordion-section-title .action {
+	float: right;
+	background: #f5f5f5;
+	color: #222;
+	border-left: 1px solid #eee;
+	font-weight: bold;
+	font-size: 12px;
+	line-height: 42px;
+	margin: -10px -10px -11px 0;
+	padding: 0 12px;
+	transition: color .1s ease-in-out,
+	            background .1s ease-in-out;
+}
+
+.customize-section-title .action {
+	background: #fff;
+	color: #0073aa;
+}
+
+.customize-section-title:hover .action,
+.customize-section-title:focus .action,
+.accordion-section-title:hover .action,
+.accordion-section-title:focus .action {
+	background: #ddd;
+	color: #000;
+	border-left-color: #d9d9d9
+}
+
+.customize-section-title:hover .action,
+.customize-section-title:focus .action {
+	background: #0073aa;
+	color: #fff;
+}
+
 #customize-theme-controls .customize-themes-panel .accordion-section-content {
 	background: transparent;
 	display: block;
@@ -889,15 +960,9 @@
 
 /* Panel-like behavior */
 #accordion-section-themes .accordion-section-title:after {
-	content: "\f148";
+	display: none;
 }
 
-.rtl #accordion-section-themes .accordion-section-title:after {
-	-webkit-transform: rotate(180deg);
-	-ms-transform: rotate(180deg);
-	transform: rotate(180deg);
-}
-
 #customize-theme-controls .control-section.current-panel > h3.accordion-section-title {
 	left: 0;
 }
Index: src/wp-admin/js/customize-controls.js
===================================================================
--- src/wp-admin/js/customize-controls.js	(revision 31634)
+++ src/wp-admin/js/customize-controls.js	(working copy)
@@ -573,7 +573,7 @@
 			var section = this;
 
 			// Expand/Collapse section/panel.
-			section.container.find( '.accordion-section-title' ).on( 'click keydown', function( event ) {
+			section.container.find( '.accordion-section-title, .customize-section-title' ).on( 'click keydown', function( event ) {
 				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 					return;
 				}
@@ -586,16 +586,6 @@
 				}
 			});
 
-			section.container.find( '.themes-panel-back' ).on( 'click keydown', function( event ) {
-				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
-					return;
-				}
-
-				event.preventDefault(); // Keep this AFTER the key filter above
-
-				section.collapse();
-			});
-
 			// Theme navigation in details view.
 			section.container.on( 'click keydown', '.left', function( event ) {
 				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
@@ -679,7 +669,7 @@
 				container = section.closest( '.accordion-container' ),
 				siblings = container.find( '.open' ),
 				topPanel = overlay.find( '#customize-theme-controls > ul > .accordion-section > .accordion-section-title' ).add( '#customize-info > .accordion-section-title' ),
-				backBtn = overlay.find( '.themes-panel-back' ),
+				backBtn = section.find( '.customize-section-title' ),
 				panelTitle = section.find( '.accordion-section-title' ).first(),
 				content = section.find( '.control-panel-content' );
 
@@ -709,7 +699,6 @@
 					}
 				} );
 				topPanel.attr( 'tabindex', '-1' );
-				backBtn.attr( 'tabindex', '0' );
 				backBtn.focus();
 			} else {
 				siblings.removeClass( 'open' );
@@ -722,7 +711,6 @@
 					}
 				} );
 				topPanel.attr( 'tabindex', '0' );
-				backBtn.attr( 'tabindex', '-1' );
 				panelTitle.focus();
 				container.scrollTop( 0 );
 			}
Index: src/wp-includes/class-wp-customize-manager.php
===================================================================
--- src/wp-includes/class-wp-customize-manager.php	(revision 31634)
+++ src/wp-includes/class-wp-customize-manager.php	(working copy)
@@ -1139,6 +1139,9 @@
 		// Theme Controls.
 		$themes = wp_prepare_themes_for_js();
 		foreach ( $themes as $theme ) {
+			if ( $theme['active'] ) {
+				continue;
+			}
 			$theme_id = 'theme_' . $theme['id'];
 			$this->add_control( new WP_Customize_Theme_Control( $this, $theme_id, array(
 				'theme' => $theme,
Index: src/wp-includes/class-wp-customize-section.php
===================================================================
--- src/wp-includes/class-wp-customize-section.php	(revision 31634)
+++ src/wp-includes/class-wp-customize-section.php	(working copy)
@@ -343,16 +343,24 @@
 		<li id="accordion-section-<?php echo esc_attr( $this->id ); ?>" class="<?php echo esc_attr( $classes ); ?>">
 			<h3 class="accordion-section-title" tabindex="0">
 				<?php echo esc_html( $this->title ); ?>
-				<span class="screen-reader-text"><?php _e( 'Press return or enter to expand' ); ?></span>
+				<span class="action"><?php _e( 'Change' ); ?></span>
+				<span class="screen-reader-text"><?php _e( 'Press return or enter to change themes' ); ?></span>
 			</h3>
-			<span class="control-panel-back themes-panel-back" tabindex="-1"><span class="screen-reader-text"><?php _e( 'Back' ); ?></span></span>
 			<div class="customize-themes-panel control-panel-content themes-php">
-				<h2><?php esc_html_e( 'Themes' ); ?>
-					<span class="title-count theme-count"><?php echo count( $this->controls ) - 1; ?></span>
-				<?php if ( ! is_multisite() && current_user_can( 'install_themes' ) ) : ?>
-					<a href="<?php echo admin_url( 'theme-install.php' ); ?>" target="_top" class="add-new-h2"><?php echo esc_html_x( 'Add New', 'Add new theme' ); ?></a>
-				<?php endif; ?>
-				</h2>
+				<div class="customize-info">
+					<span class="preview-notice"><span class="preview-action"><?php
+						echo sprintf( __( 'You are browsing %s' ), '</span><strong class="panel-title">' . __( 'Themes' ) . '</strong>' );
+					?><span class="title-count theme-count"><?php echo count( $this->controls ) - 1; ?></span>
+					</span>
+					<?php if ( ! is_multisite() && current_user_can( 'install_themes' ) ) : ?>
+						<a href="<?php echo admin_url( 'theme-install.php' ); ?>" target="_top" class="button"><?php echo esc_html_x( 'Add New', 'Add new theme' ); ?></a>
+					<?php endif; ?>
+				</div>
+				<h3 class="customize-section-title" tabindex="0">
+					<?php echo sprintf( __( 'Previewing: %s' ), $this->manager->theme()->display('Name') ); ?>
+					<span class="action"><?php _e( 'Customize' ); ?></span>
+					<span class="screen-reader-text"><?php _e( 'Press return or enter to return to customize' ); ?></span>
+				</h3>
 				<div class="theme-overlay" tabindex="0" role="dialog" aria-label="<?php esc_attr_e( 'Theme details' ); ?>"></div>
 				<div id="customize-container"></div>
 				<?php if ( 6 < count( $this->controls ) ) : ?>