MC-3812: Text/Banner - Stage Inline Editor becomes focused and editable after clicking Save button on Edit Form

- Resolve issue with fixRangeSelection function

Author: davemacaulay

lib/web/mage/adminhtml/wysiwyg/tiny_mce/tinymce4Adapter.js

@@ -559,10 +559,12 @@ define([
             var selection = editor.selection,
                 dom = editor.dom,
                 rng = dom.createRng(),
+                doc = editor.getDoc(),
                 markerHtml,
                 marker;
 
-            if (!selection.getContent().length) {
+            // Validate the range we're trying to fix is contained within the current editors document
+            if (!selection.getContent().length && jQuery.contains(doc, selection.getRng().startContainer)) {
                 markerHtml = '<span id="mce_marker" data-mce-type="bookmark">\uFEFF</span>';
                 selection.setContent(markerHtml);
                 marker = dom.get('mce_marker');