In the xml file in Eclipse, the shortcut key of ctrl+left button, click the class positioning, it does not take effect

 Modification method:
   The first method: Window -> Preferences -> General -> Editors -> File Associations 
            File types: *.xml
            Associated editors: XML Editor*** -> Default
            Associated editors In the selection box, click "XML Editor** * ", click the "Default" button.
  The second way: select an xml file in the project, right-click and select the open method "XML Editor***", and then you can