Index: wp-admin/upload.php
===================================================================
--- wp-admin/upload.php	(revision 5433)
+++ wp-admin/upload.php	(working copy)
@@ -41,7 +41,7 @@
 } else
 	$wp_upload_tabs['browse-all'] = array(__('Browse All'), 'upload_files', 'wp_upload_tab_browse', $action ? 0 : $all_atts);
 
-	$wp_upload_tabs = array_merge($wp_upload_tabs, apply_filters( 'wp_upload_tabs', array() ));
+	$wp_upload_tabs = apply_filters( 'wp_upload_tabs', $wp_upload_tabs );
 
 if ( !is_callable($wp_upload_tabs[$tab][2]) ) {
 	$to_tab = isset($wp_upload_tabs['upload']) ? 'upload' : 'browse-all';