diff --git a/blueprintcompiler/ast_utils.py b/blueprintcompiler/ast_utils.py
index 5019098..7bfacfb 100644
--- a/blueprintcompiler/ast_utils.py
+++ b/blueprintcompiler/ast_utils.py
@@ -109,9 +109,9 @@ class AstNode:
         else:
             return self.parent.root
 
-    def parent_by_type(self, type):
+    def parent_by_type(self, type: T.Type[TType]) -> TType:
         if self.parent is None:
-            return None
+            raise CompilerBugError()
         elif isinstance(self.parent, type):
             return self.parent
         else:
diff --git a/blueprintcompiler/language/__init__.py b/blueprintcompiler/language/__init__.py
index 45e5361..571f09b 100644
--- a/blueprintcompiler/language/__init__.py
+++ b/blueprintcompiler/language/__init__.py
@@ -23,7 +23,7 @@ from .gtk_menu import menu, Menu, MenuAttribute
 from .gtk_size_group import Widgets
 from .gtk_string_list import Strings
 from .gtk_styles import Styles
-from .gtkbuilder_child import Child
+from .gtkbuilder_child import Child, ChildType, ChildInternal, ChildExtension
 from .gtkbuilder_template import Template
 from .imports import GtkDirective, Import
 from .property_binding import PropertyBinding
diff --git a/blueprintcompiler/language/gobject_object.py b/blueprintcompiler/language/gobject_object.py
index a66ffe6..1dbbce5 100644
--- a/blueprintcompiler/language/gobject_object.py
+++ b/blueprintcompiler/language/gobject_object.py
@@ -22,7 +22,7 @@ import typing as T
 from functools import cached_property
 
 from .common import *
-from .response_id import ResponseId
+from .response_id import ExtResponse
 from .types import ClassName, ConcreteClassName
 
 
@@ -60,7 +60,7 @@ class Object(AstNode):
         return self.class_name.gir_type
 
     @cached_property
-    def action_widgets(self) -> T.List[ResponseId]:
+    def action_widgets(self) -> T.List[ExtResponse]:
         """Get list of widget's action widgets.
 
         Empty if object doesn't have action widgets.
@@ -69,7 +69,7 @@ class Object(AstNode):
 
         return [
             child.response_id
-            for child in self.children[ObjectContent][0].children[Child]
+            for child in self.content.children[Child]
             if child.response_id
         ]
 
diff --git a/blueprintcompiler/language/gtkbuilder_child.py b/blueprintcompiler/language/gtkbuilder_child.py
index 45b2074..c3e1c47 100644
--- a/blueprintcompiler/language/gtkbuilder_child.py
+++ b/blueprintcompiler/language/gtkbuilder_child.py
@@ -21,7 +21,7 @@
 from functools import cached_property
 
 from .gobject_object import Object
-from .response_id import ResponseId
+from .response_id import ExtResponse
 from .common import *
 
 ALLOWED_PARENTS: T.List[T.Tuple[str, str]] = [
@@ -30,20 +30,49 @@ ALLOWED_PARENTS: T.List[T.Tuple[str, str]] = [
 ]
 
 
+class ChildInternal(AstNode):
+    grammar = ["internal-child", UseIdent("internal_child")]
+
+    @property
+    def internal_child(self) -> str:
+        return self.tokens["internal_child"]
+
+
+class ChildType(AstNode):
+    grammar = UseIdent("child_type").expected("a child type")
+
+    @property
+    def child_type(self) -> str:
+        return self.tokens["child_type"]
+
+
+class ChildExtension(AstNode):
+    grammar = ExtResponse
+
+    @property
+    def child(self) -> ExtResponse:
+        return self.children[0]
+
+
+class ChildAnnotation(AstNode):
+    grammar = ["[", AnyOf(ChildInternal, ChildExtension, ChildType), "]"]
+
+    @property
+    def child(self) -> T.Union[ChildInternal, ChildExtension, ChildType]:
+        return self.children[0]
+
+
 class Child(AstNode):
     grammar = [
-        Optional(
-            [
-                "[",
-                Optional(["internal-child", UseLiteral("internal_child", True)]),
-                UseIdent("child_type").expected("a child type"),
-                Optional(ResponseId),
-                "]",
-            ]
-        ),
+        Optional(ChildAnnotation),
         Object,
     ]
 
+    @property
+    def annotation(self) -> T.Optional[ChildAnnotation]:
+        annotations = self.children[ChildAnnotation]
+        return annotations[0] if len(annotations) else None
+
     @property
     def object(self) -> Object:
         return self.children[Object][0]
@@ -69,15 +98,17 @@ class Child(AstNode):
                 )
 
     @cached_property
-    def response_id(self) -> T.Optional[ResponseId]:
+    def response_id(self) -> T.Optional[ExtResponse]:
         """Get action widget's response ID.
 
         If child is not action widget, returns `None`.
         """
-        response_ids = self.children[ResponseId]
-
-        if response_ids:
-            return response_ids[0]
+        if (
+            self.annotation is not None
+            and isinstance(self.annotation.child, ChildExtension)
+            and isinstance(self.annotation.child.child, ExtResponse)
+        ):
+            return self.annotation.child.child
         else:
             return None
 
diff --git a/blueprintcompiler/language/response_id.py b/blueprintcompiler/language/response_id.py
index e3b44a9..7de197c 100644
--- a/blueprintcompiler/language/response_id.py
+++ b/blueprintcompiler/language/response_id.py
@@ -23,12 +23,13 @@ import typing as T
 from .common import *
 
 
-class ResponseId(AstNode):
+class ExtResponse(AstNode):
     """Response ID of action widget."""
 
     ALLOWED_PARENTS: T.List[T.Tuple[str, str]] = [("Gtk", "Dialog"), ("Gtk", "InfoBar")]
 
     grammar = [
+        Keyword("action"),
         Keyword("response"),
         "=",
         AnyOf(
@@ -41,13 +42,6 @@ class ResponseId(AstNode):
         Optional([Keyword("default"), UseLiteral("is_default", True)]),
     ]
 
-    @validate()
-    def child_type_is_action(self) -> None:
-        """Check that child type is "action"."""
-        child_type = self.parent.tokens["child_type"]
-        if child_type != "action":
-            raise CompileError(f"Only action widget can have response ID")
-
     @validate()
     def parent_has_action_widgets(self) -> None:
         """Chech that parent widget has allowed type."""
@@ -59,7 +53,7 @@ class ResponseId(AstNode):
 
         gir = self.root.gir
 
-        for namespace, name in ResponseId.ALLOWED_PARENTS:
+        for namespace, name in ExtResponse.ALLOWED_PARENTS:
             parent_type = gir.get_type(name, namespace)
             if container_type.assignable_to(parent_type):
                 break
@@ -71,10 +65,10 @@ class ResponseId(AstNode):
     @validate()
     def widget_have_id(self) -> None:
         """Check that action widget have ID."""
-        from .gobject_object import Object
+        from .gtkbuilder_child import Child
 
-        _object = self.parent.children[Object][0]
-        if _object.tokens["id"] is None:
+        object = self.parent_by_type(Child).object
+        if object.id is None:
             raise CompileError(f"Action widget must have ID")
 
     @validate("response_id")
@@ -102,10 +96,9 @@ class ResponseId(AstNode):
     @validate("default")
     def no_multiple_default(self) -> None:
         """Only one action widget in dialog can be default."""
-        from .gtkbuilder_child import Child
         from .gobject_object import Object
 
-        if not self.tokens["is_default"]:
+        if not self.is_default:
             return
 
         action_widgets = self.parent_by_type(Object).action_widgets
@@ -126,7 +119,7 @@ class ResponseId(AstNode):
     @property
     def widget_id(self) -> str:
         """Get action widget ID."""
-        from .gobject_object import Object
+        from .gtkbuilder_child import Child
 
-        _object: Object = self.parent.children[Object][0]
-        return _object.tokens["id"]
+        object = self.parent_by_type(Child).object
+        return object.id
diff --git a/blueprintcompiler/outputs/xml/__init__.py b/blueprintcompiler/outputs/xml/__init__.py
index 607cc36..8332cee 100644
--- a/blueprintcompiler/outputs/xml/__init__.py
+++ b/blueprintcompiler/outputs/xml/__init__.py
@@ -170,11 +170,16 @@ class XmlOutput(OutputFormat):
 
     def _emit_child(self, child: Child, xml: XmlEmitter):
         child_type = internal_child = None
-
-        if child.tokens["internal_child"]:
-            internal_child = child.tokens["child_type"]
-        else:
-            child_type = child.tokens["child_type"]
+        if child.annotation is not None:
+            annotation = child.annotation.child
+            if isinstance(annotation, ChildType):
+                child_type = annotation.child_type
+            elif isinstance(annotation, ChildInternal):
+                internal_child = annotation.internal_child
+            elif isinstance(annotation, ChildExtension):
+                child_type = "action"
+            else:
+                raise CompilerBugError()
 
         xml.start_tag("child", type=child_type, internal_child=internal_child)
         self._emit_object(child.object, xml)
diff --git a/tests/sample_errors/action_widget_have_no_id.err b/tests/sample_errors/action_widget_have_no_id.err
index 74ff665..b239d77 100644
--- a/tests/sample_errors/action_widget_have_no_id.err
+++ b/tests/sample_errors/action_widget_have_no_id.err
@@ -1 +1 @@
-4,13,15,Action widget must have ID
+4,6,22,Action widget must have ID
diff --git a/tests/sample_errors/action_widget_in_invalid_container.err b/tests/sample_errors/action_widget_in_invalid_container.err
index 20950a1..ef3296c 100644
--- a/tests/sample_errors/action_widget_in_invalid_container.err
+++ b/tests/sample_errors/action_widget_in_invalid_container.err
@@ -1 +1 @@
-4,13,11,Gtk.Box doesn't have action widgets
+4,6,18,Gtk.Box doesn't have action widgets
diff --git a/tests/sample_errors/action_widget_not_action.blp b/tests/sample_errors/action_widget_not_action.blp
deleted file mode 100644
index cd760e5..0000000
--- a/tests/sample_errors/action_widget_not_action.blp
+++ /dev/null
@@ -1,8 +0,0 @@
-using Gtk 4.0;
-
-Dialog {
-    [some_type response=ok]
-    Button ok_button {
-
-    }
-}
diff --git a/tests/sample_errors/action_widget_not_action.err b/tests/sample_errors/action_widget_not_action.err
deleted file mode 100644
index 95699ff..0000000
--- a/tests/sample_errors/action_widget_not_action.err
+++ /dev/null
@@ -1 +0,0 @@
-4,16,11,Only action widget can have response ID
diff --git a/tests/test_samples.py b/tests/test_samples.py
index 7af9e1b..88cecdf 100644
--- a/tests/test_samples.py
+++ b/tests/test_samples.py
@@ -216,7 +216,6 @@ class TestSamples(unittest.TestCase):
         self.assert_sample_error("action_widget_float_response")
         self.assert_sample_error("action_widget_have_no_id")
         self.assert_sample_error("action_widget_multiple_default")
-        self.assert_sample_error("action_widget_not_action")
         self.assert_sample_error("action_widget_in_invalid_container")
         self.assert_sample_error("action_widget_response_dne")
         self.assert_sample_error("action_widget_negative_response")