Ticket #4768: 4768.patch

_source/plugins/contextmenu/plugin.js

@@ -88 +88 @@
                                         menu.onHide = null;
 
                                         if ( CKEDITOR.env.ie )
-                                                editor.getSelection().unlock();
+                                        {
+                                                var selection = editor.getSelection();
+                                                selection && selection.unlock();
+                                        }
 
                                         this.onHide && this.onHide();
                                 },
@@ -181 +184 @@
                                 element.on( 'mousedown', function( event )
                                 {
                                         if ( event.data.$.button == 2 )
-                                                this.editor.getSelection().lock();
+                                        {
+                                                var selection = this.editor.getSelection();
+                                                selection && selection.lock();
+                                        }
                                 }, this );
                         }