diff --git a/basis/ui/gestures/gestures.factor b/basis/ui/gestures/gestures.factor
index 180447ff4f..2f7bee927b 100644
--- a/basis/ui/gestures/gestures.factor
+++ b/basis/ui/gestures/gestures.factor
@@ -82,7 +82,7 @@ SYMBOLS: C+ A+ M+ S+ ;
 TUPLE: key-down mods sym ;
 
 : <key-gesture> ( mods sym action? class -- mods' sym' )
-    [ [ S+ rot remove swap ] unless ] dip boa ; inline
+    [ [ [ S+ swap remove f like ] dip ] unless ] dip boa ; inline
 
 : <key-down> ( mods sym action? -- key-down )
     key-down <key-gesture> ;
diff --git a/basis/ui/x11/x11.factor b/basis/ui/x11/x11.factor
index 9faf888559..de57c2dc72 100644
--- a/basis/ui/x11/x11.factor
+++ b/basis/ui/x11/x11.factor
@@ -7,7 +7,7 @@ x11.events x11.xim x11.glx x11.clipboard x11.constants
 x11.windows io.encodings.string io.encodings.ascii
 io.encodings.utf8 combinators debugger command-line qualified
 math.vectors classes.tuple opengl.gl threads math.geometry.rect
-environment ;
+environment ascii ;
 IN: ui.x11
 
 SINGLETON: x11-ui-backend
@@ -67,18 +67,26 @@ M: world configure-event
 : event-modifiers ( event -- seq )
     XKeyEvent-state modifiers modifier ;
 
+: valid-input? ( string gesture -- ? )
+    over empty? [ 2drop f ] [
+        mods>> { f { S+ } } member? [
+            [ [ 127 = not ] [ CHAR: \s >= ] bi and ] all?
+        ] [
+            [ [ 127 = not ] [ CHAR: \s >= ] [ alpha? not ] tri and and ] all?
+        ] if
+    ] if ;
+
 : key-down-event>gesture ( event world -- string gesture )
     dupd
     handle>> xic>> lookup-string
     >r swap event-modifiers r> key-code <key-down> ;
 
-: valid-input? ( string -- ? )
-    [ f ] [ [ [ 127 = not ] [ CHAR: \s >= ] bi and ] all? ] if-empty ;
-
 M: world key-down-event
     [ key-down-event>gesture ] keep
-    world-focus [ propagate-gesture ] keep
-    over valid-input? [ user-input ] [ 2drop ] if ;
+    world-focus
+    [ propagate-gesture drop ]
+    [ 2over valid-input? [ nip user-input ] [ 3drop ] if ]
+    3bi ;
 
 : key-up-event>gesture ( event -- gesture )
     dup event-modifiers swap 0 XLookupKeysym key-code <key-up> ;