Index: includes/OutputPage.php
===================================================================
--- includes/OutputPage.php	(revision 31239)
+++ includes/OutputPage.php	(working copy)
@@ -297,9 +297,12 @@
 		$lb->addResultToCache( LinkCache::singleton(), $res );
 
 		# Remove categories with hiddencat
-		foreach ( $res as $row ) {
-			if ( isset( $row->pp_value ) ) {
-				unset( $categories[$row->page_title] );
+		global $wgTitle;
+		if( $wgTitle->getNamespace() != NS_CATEGORY ) {
+			foreach ( $res as $row ) {
+				if ( isset( $row->pp_value ) ) {
+					unset( $categories[$row->page_title] );
+				}
 			}
 		}