src/Pure/Isar/isar_syn.ML

 val _ =
   Outer_Syntax.command @{command_spec "context"} "begin local theory context"
     ((Parse.position Parse.xname >> (fn name =>
         Toplevel.begin_local_theory true (Named_Target.begin name)) ||
       Scan.optional Parse_Spec.includes [] -- Scan.repeat Parse_Spec.context_element
-        >> (fn (incls, elems) => Toplevel.open_target (Bundle.context_cmd incls elems)))
+        >> (fn (incls, elems) => Toplevel.open_target (#2 o Bundle.context_cmd incls elems)))
       --| Parse.begin);
 
 
 (* locales *)