Index: SelectCategory/SelectCategory_body.php
===================================================================
--- SelectCategory/SelectCategory_body.php	(revision 115794)
+++ SelectCategory/SelectCategory_body.php	(working copy)
@@ -317,7 +317,7 @@
 
 		if ($enabledForNamespace
 			&& (!$isSubpage
-				|| $isSubpage && $wgSelectCategoryEnableSubpage)
+				|| $isSubpage && $wgSelectCategoryEnableSubpages)
 			&& $pageObj->section == false) {
 			return true;
 		}