Ensure ChatMessage internals are visible to Panel (#6304)

panel/chat/message.py

@@ -14,7 +14,8 @@
 from tempfile import NamedTemporaryFile
 from textwrap import indent
 from typing import (
-    TYPE_CHECKING, Any, ClassVar, Dict, Iterable, List, Union,
+    TYPE_CHECKING, Any, Callable, ClassVar, Dict, Iterable, List, Optional,
+    Union,
 )
 from zoneinfo import ZoneInfo
 
@@ -687,6 +688,11 @@ def update(
             updates["object"] = value
         self.param.update(**updates)
 
+    def select(
+        self, selector: Optional[type | Callable[[Viewable], bool]] = None
+    ) -> List[Viewable]:
+        return super().select(selector) + self._composite.select(selector)
+
     def serialize(
         self,
         prefix_with_viewable_label: bool = True,