Ticket #7639: 7639_3.patch

_source/plugins/selection/plugin.js

@@ -477 +477 @@
                                 });
 
                         editor.selectionChange = checkSelectionChangeTimeout;
+
+                        // IE9 might cease to work if there's an object selection inside the iframe (#7639).
+                        CKEDITOR.env.ie9Compat && editor.on( 'destroy', function()
+                        {
+                                var sel = editor.getSelection();
+                                sel && sel.getNative().clear();
+                        }, null, null, 9 );
                 }
         });