In Windows 7, when you double-click or press Enter on folders in the right pane of Windows Explorer to open them, the folder tree in the left pane does not automatically expand to show where you are. By default, the navigation pane stays at the top level if you use the right pane to navigate through folders. You have to manually expand the navigation pane tree. Prior versions of Windows, including Vista and XP, automatically expanded the folder tree to show the location of the folder opened in the right pane.
To change this option, open Windows Explorer and select 'Folder and search options' from the Organize menu. In the Navigation pane section of the Folder Options dialog box, select the 'Automatically expand to current folder' checkbox. You can also choose to view the classic navigation tree used in Vista and XP. To do this, select the 'Show all folders' checkbox in the Navigation pane section on the Folder Options dialog box. Click OK to save your changes and close the dialog box.