diff --git a/extra/ui/x11/x11.factor b/extra/ui/x11/x11.factor
index 2b1a5ba331..5984e3decd 100755
--- a/extra/ui/x11/x11.factor
+++ b/extra/ui/x11/x11.factor
@@ -5,7 +5,7 @@ ui.clipboards ui.gadgets.worlds assocs kernel math namespaces
 opengl sequences strings x11.xlib x11.events x11.xim x11.glx
 x11.clipboard x11.constants x11.windows io.utf8 combinators
 debugger system command-line ui.render math.vectors tuples
-opengl.gl ;
+opengl.gl threads ;
 IN: ui.x11
 
 TUPLE: x11-ui-backend ;