Index: themes.php
===================================================================
--- themes.php	(revision 18401)
+++ themes.php	(working copy)
@@ -118,6 +118,13 @@
 		}
 	}
 	echo implode ( ' | ', $options );
+	
+	if ( current_user_can( 'edit_themes' ) && ! empty( $ct->parent_theme ) ) {
+	/* translators: 1: theme title, 2:  template dir, 3: stylesheet_dir, 4: theme title, 5: parent_theme */ ?>
+		<p><?php printf( __( 'The template files are located in <code>%2$s</code>. The stylesheet files are located in <code>%3$s</code>. <strong>%4$s</strong> uses templates from <strong>%5$s</strong>. Changes made to the templates will affect both themes.' ), $title, str_replace( WP_CONTENT_DIR, '', $ct->template_dir ), str_replace( WP_CONTENT_DIR, '', $ct->stylesheet_dir ), $ct->title, $ct->parent_theme ); ?></p>
+	<?php } else { ?>
+		<p><?php printf( __( 'All of this theme&#8217;s files are located in <code>%2$s</code>.' ), $title, str_replace( WP_CONTENT_DIR, '', $ct->template_dir ), str_replace( WP_CONTENT_DIR, '', $ct->stylesheet ) ); ?></p>
+	<?php }
 
 	if ( $ct->tags ) : ?>
 	<p><?php _e('Tags:'); ?> <?php echo join(', ', $ct->tags); ?></p>