Editor: ensure there is a selection before getting the caret position. Fixes a bug in Firefox when there is no selection for a hidden element.

Props johnschulz, azaozz.

Fixes #43012 for trunk.
Built from https://develop.svn.wordpress.org/trunk@42430


git-svn-id: http://core.svn.wordpress.org/trunk@42260 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/editor.js

@@ -695,10 +695,10 @@ window.wp = window.wp || {};
 		 */
 		function findBookmarkedPosition( editor ) {
 			// Get the TinyMCE `window` reference, since we need to access the raw selection.
-			var TinyMCEWIndow = editor.getWin(),
-				selection = TinyMCEWIndow.getSelection();
+			var TinyMCEWindow = editor.getWin(),
+				selection = TinyMCEWindow.getSelection();
 
-			if ( selection.rangeCount <= 0 ) {
+			if ( ! selection || selection.rangeCount < 1 ) {
 				// no selection, no need to continue.
 				return;
 			}

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.0-alpha-42429';
+$wp_version = '5.0-alpha-42430';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.