If rendering an error popup fails, don't open an endless stream

basis/ui/gadgets/worlds/worlds.factor

@@ -30,7 +30,7 @@ ERROR: no-world-found ;
 
 : (request-focus) ( child world ? -- )
     pick parent>> pick eq? [
-        >r >r dup parent>> dup r> r>
+        [ dup parent>> dup ] 2dip
         [ (request-focus) ] keep
     ] unless focus-child ;
 
@@ -80,7 +80,7 @@ SYMBOL: ui-error-hook
 : ui-error ( error -- )
     ui-error-hook get [ call ] [ print-error ] if* ;
 
-[ rethrow ] ui-error-hook set-global
+ui-error-hook global [ [ rethrow ] or ] change-at
 
 : draw-world ( world -- )
     dup draw-world? [

basis/ui/tools/debugger/debugger.factor

@@ -35,7 +35,15 @@ M: debugger focusable-child* restarts>> ;
     #! No restarts for the debugger window
     f [ drop ] <debugger> "Error" open-window ;
 
-[ debugger-window ] ui-error-hook set-global
+GENERIC: error-in-debugger? ( error -- ? )
+
+M: world-error error-in-debugger? world>> gadget-child debugger? ;
+
+M: object error-in-debugger? drop f ;
+
+[
+    dup error-in-debugger? [ rethrow ] [ debugger-window ] if 
+] ui-error-hook set-global
 
 M: world-error error.
     "An error occurred while drawing the world " write