diff --git a/basis/ui/tools/walker/walker.factor b/basis/ui/tools/walker/walker.factor
index 80e9ced009..02a7493256 100644
--- a/basis/ui/tools/walker/walker.factor
+++ b/basis/ui/tools/walker/walker.factor
@@ -1,6 +1,6 @@
 ! Copyright (C) 2006, 2009 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors colors kernel concurrency.messaging colors.constants inspector
+USING: accessors colors kernel concurrency.messaging colors.constants inspector formatting
 ui.tools.listener ui.tools.traceback ui.gadgets.buttons ui.gadgets.colors
 ui.gadgets.status-bar ui.gadgets.toolbar ui.gadgets.tracks ui.commands ui.gadgets
 models models.arrow ui.tools.browser ui.tools.common ui.gestures