diff --git a/basis/ui/render/render.factor b/basis/ui/render/render.factor
index 872c50f6eb..6bc5f0f51f 100644
--- a/basis/ui/render/render.factor
+++ b/basis/ui/render/render.factor
@@ -1,8 +1,9 @@
 ! Copyright (C) 2005, 2009 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: math.rectangles math.vectors namespaces kernel accessors
-assocs combinators sequences opengl opengl.gl colors
+assocs combinators sequences sets opengl opengl.gl colors
 colors.constants ui.gadgets ui.pens ;
+FROM: namespaces => set ;
 IN: ui.render
 
 SYMBOL: clip
@@ -94,7 +95,7 @@ M: gadget gadget-foreground dup interior>> pen-foreground ;
 : draw-background ( gadget -- )
     origin get [
         [
-            dup selected-gadgets get key?
+            dup selected-gadgets get in?
             [ draw-selection-background ]
             [ draw-standard-background ] if
         ] [ draw-gadget* ] bi
diff --git a/basis/ui/traverse/traverse.factor b/basis/ui/traverse/traverse.factor
index 5a92a4cea2..d5e51d5804 100644
--- a/basis/ui/traverse/traverse.factor
+++ b/basis/ui/traverse/traverse.factor
@@ -89,12 +89,12 @@ M: node gadget-text*
 : gadget-at-path ( parent path -- gadget )
     [ swap nth-gadget ] each ;
 
-GENERIC# leaves* 1 ( tree assoc -- )
+GENERIC# leaves* 1 ( tree set -- )
 
 M: node leaves* [ children>> ] dip leaves* ;
 
 M: array leaves* '[ _ leaves* ] each ;
 
-M: gadget leaves* conjoin ;
+M: gadget leaves* adjoin ;
 
-: leaves ( tree -- assoc ) H{ } clone [ leaves* ] keep ;
+: leaves ( tree -- set ) HS{ } clone [ leaves* ] keep ;