diff --git a/libraries/structure.lib.php b/libraries/structure.lib.php
index 5d828efb42..a34d94e23f 100644
--- a/libraries/structure.lib.php
+++ b/libraries/structure.lib.php
@@ -338,7 +338,8 @@ function PMA_getHtmlForCheckAllTables($pmaThemeImage, $text_dir,
             . __('Replace table prefix') . '</option>' . "\n";
         $html_output .= '<option value="copy_tbl_change_prefix" >'
             . __('Copy table with prefix') . '</option>' . "\n";
-        if ($GLOBALS['cfgRelation']['central_columnswork']) {
+        if (isset($GLOBALS['cfgRelation']['central_columnswork'])
+        && $GLOBALS['cfgRelation']['central_columnswork']) {
             $html_output .= '<option value="sync_unique_columns_central_list" >'
                 . __('Add columns to central list') . '</option>' . "\n";
             $html_output .= '<option value="delete_unique_columns_central_list" >'