Editor: When switching Editor tabs, don't scroll unnecessarily.

- When switching to the Text view, wait until after the Visual editor element has been hidden, before focussing the `<textarea>`.
- When switching to the Visual view, only scroll if the cursor is not visible on the current screen.

Merge of 52175 to the 4.9 branch.

Fixes #42530.


Built from https://develop.svn.wordpress.org/branches/4.9@42176


git-svn-id: http://core.svn.wordpress.org/branches/4.9@42006 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/editor.js

@@ -635,6 +635,11 @@ window.wp = window.wp || {};
 				selectionPosition = TinyMCEContentAreaTop + elementTop,
 				visibleAreaHeight = windowHeight - ( edToolsHeight + toolbarHeight );
 
+			// There's no need to scroll if the selection is inside the visible area.
+			if ( selectionPosition < visibleAreaHeight ) {
+				return;
+			}
+
 			/**
 			 * The minimum scroll height should be to the top of the editor, to offer a consistent
 			 * experience.
@@ -852,19 +857,16 @@ window.wp = window.wp || {};
 				end = selection.end || selection.start;
 
 			if ( textArea.focus ) {
-				// focus and scroll to the position
+				// Wait for the Visual editor to be hidden, then focus and scroll to the position
 				setTimeout( function() {
+					textArea.setSelectionRange( start, end );
 					if ( textArea.blur ) {
 						// defocus before focusing
 						textArea.blur();
 					}
 					textArea.focus();
 				}, 100 );
-
-				textArea.focus();
 			}
-
-			textArea.setSelectionRange( start, end );
 		}
 
 		// Restore the selection when the editor is initialized. Needed when the Text editor is the default.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-RC2-42174';
+$wp_version = '4.9-RC2-42176';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.