Ticket #19077: 19077.2.patch

wp-admin/includes/screen.php

@@ -519 +519 @@
         function set_current_screen() {
                 global $current_screen, $taxnow, $typenow;
                 $current_screen = $this;
-                $taxnow = $this->taxonomy;
-                $typenow = $this->post_type;
+                if ( !empty( $this->taxonomy ) )
+                        $taxnow = $this->taxonomy;
+                if ( !empty( $this->post_type ) )
+                        $typenow = $this->post_type;
                 $current_screen = apply_filters( 'current_screen', $current_screen );
         }