Customize: Allow tab characters in custom CSS input.

Pressing `Esc` followed by `Tab` allows for tabbing to the next element.

Props afercia, coffee2code, westonruter.
See #35395.
Fixes #38667.

Built from https://develop.svn.wordpress.org/trunk@39149


git-svn-id: http://core.svn.wordpress.org/trunk@39089 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/css/customize-controls-rtl.css

@@ -1129,6 +1129,10 @@ p.customize-section-description {
 	margin-right: 10px;
 	margin-left: 10px;
 }
+#customize-theme-controls #sub-accordion-section-custom_css textarea {
+	-moz-tab-size: 4;
+	tab-size: 4;
+}
 
 #sub-accordion-section-custom_css .customize-control-notifications-container {
 	margin-bottom: 15px;

wp-admin/css/customize-controls.css

@@ -1129,6 +1129,10 @@ p.customize-section-description {
 	margin-left: 10px;
 	margin-right: 10px;
 }
+#customize-theme-controls #sub-accordion-section-custom_css textarea {
+	-moz-tab-size: 4;
+	tab-size: 4;
+}
 
 #sub-accordion-section-custom_css .customize-control-notifications-container {
 	margin-bottom: 15px;

wp-admin/js/customize-controls.js

@@ -5234,6 +5234,53 @@
 			});
 		});
 
+		// Allow tabs to be entered in Custom CSS textarea.
+		api.control( 'custom_css', function setupCustomCssControl( control ) {
+			control.deferred.embedded.done( function allowTabs() {
+				var $textarea = control.container.find( 'textarea' ), textarea = $textarea[0];
+
+				$textarea.on( 'blur', function onBlur() {
+					$textarea.data( 'next-tab-blurs', false );
+				} );
+
+				$textarea.on( 'keydown', function onKeydown( event ) {
+					var selectionStart, selectionEnd, value, scroll, tabKeyCode = 9, escKeyCode = 27;
+
+					if ( escKeyCode === event.keyCode ) {
+						if ( ! $textarea.data( 'next-tab-blurs' ) ) {
+							$textarea.data( 'next-tab-blurs', true );
+							event.stopPropagation(); // Prevent collapsing the section.
+						}
+						return;
+					}
+
+					// Short-circuit if tab key is not being pressed or if a modifier key *is* being pressed.
+					if ( tabKeyCode !== event.keyCode || event.ctrlKey || event.altKey || event.shiftKey ) {
+						return;
+					}
+
+					// Prevent capturing Tab characters if Esc was pressed.
+					if ( $textarea.data( 'next-tab-blurs' ) ) {
+						return;
+					}
+
+					selectionStart = textarea.selectionStart;
+					selectionEnd = textarea.selectionEnd;
+					value = textarea.value;
+
+					if ( selectionStart >= 0 ) {
+						scroll = $textarea.scrollTop;
+						textarea.value = value.substring( 0, selectionStart ).concat( '\t', value.substring( selectionEnd ) );
+						$textarea.selectionStart = textarea.selectionEnd = selectionStart + 1;
+						textarea.scrollTop = scroll;
+					}
+
+					event.stopPropagation();
+					event.preventDefault();
+				} );
+			} );
+		} );
+
 		// Update the setting validities.
 		api.previewer.bind( 'selective-refresh-setting-validities', function handleSelectiveRefreshedSettingValidities( settingValidities ) {
 			api._handleSettingValidities( {

wp-includes/class-wp-customize-manager.php

@@ -3590,7 +3590,7 @@ final class WP_Customize_Manager {
 			'priority'           => 200,
 			'description_hidden' => true,
 			'description'        => sprintf( '%s<br /><a href="%s" class="external-link" target="_blank">%s<span class="screen-reader-text">%s</span></a>',
-				__( 'CSS allows you to customize the appearance and layout of your site with code. Separate CSS is saved for each of your themes.' ),
+				__( 'CSS allows you to customize the appearance and layout of your site with code. Separate CSS is saved for each of your themes. In the editing area the Tab key enters a tab character. To move below this area by pressing Tab, press the Esc key followed by the Tab key.' ),
 				'https://codex.wordpress.org/Know_Your_Sources#CSS',
 				__( 'Learn more about CSS' ),
 				__( '(link opens in a new window)' )

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-beta2-39148';
+$wp_version = '4.7-beta2-39149';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.