diff --git a/README.md b/README.md
index cca7f52..842adfa 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,7 @@ It's basiclly a wrapper of streamlit officeial elements including the chat elemn
 - support streaming output.
 - support markdown/image/video/audio messages, and all streamlit elements could be supported by customized `OutputElement`.
 - output multiple messages at once, and make them collapsable.
+- maintain session state context bound to chat conversation
 - export & import chat histories
 
 This make it easy to chat with langchain LLMs in streamlit.
@@ -46,13 +47,21 @@ import simplejson as json
 
 llm = FakeLLM()
 chat_box = ChatBox()
+chat_box.use_chat_name("chat1") # add a chat conversatoin
+
+def on_chat_change():
+    chat_box.use_chat_name(st.session_state["chat_name"])
+    chat_box.context_to_session() # restore widget values to st.session_state when chat name changed
 
 
 with st.sidebar:
     st.subheader('start to chat using streamlit')
-    streaming = st.checkbox('streaming', True)
-    in_expander = st.checkbox('show messages in expander', True)
-    show_history = st.checkbox('show history', False)
+    chat_name = st.selectbox("Chat Session:", ["default", "chat1"], key="chat_name", on_change=on_chat_change)
+    chat_box.use_chat_name(chat_name)
+    streaming = st.checkbox('streaming', key="streaming")
+    in_expander = st.checkbox('show messages in expander', key="in_expander")
+    show_history = st.checkbox('show session state', key="show_history")
+    chat_box.context_from_session(exclude=["chat_name"]) # save widget values to chat context
 
     st.divider()
 
@@ -71,6 +80,22 @@ with st.sidebar:
 chat_box.init_session()
 chat_box.output_messages()
 
+def on_feedback(
+    feedback,
+    chat_history_id: str = "",
+    history_index: int = -1,
+):
+    reason = feedback["text"]
+    score_int = chat_box.set_feedback(feedback=feedback, history_index=history_index) # convert emoji to integer
+    # do something
+    st.session_state["need_rerun"] = True
+
+
+feedback_kwargs = {
+    "feedback_type": "thumbs",
+    "optional_text_label": "wellcome to feedback",
+}
+
 if query := st.chat_input('input your question here'):
     chat_box.user_say(query)
     if streaming:
@@ -91,6 +116,11 @@ if query := st.chat_input('input your question here'):
         # update the element without focus
         chat_box.update_msg(text, element_index=0, streaming=False, state="complete")
         chat_box.update_msg("\n\n".join(docs), element_index=1, streaming=False, state="complete")
+        chat_history_id = "some id"
+        chat_box.show_feedback(**feedback_kwargs,
+                                key=chat_history_id,
+                                on_submit=on_feedback,
+                                kwargs={"chat_history_id": chat_history_id, "history_index": len(chat_box.history) - 1})
     else:
         text, docs = llm.chat(query)
         chat_box.ai_say(
@@ -156,7 +186,8 @@ if btns.button("clear history"):
 
 
 if show_history:
-    st.write(chat_box.history)
+    st.write(st.session_state)
+
 ```
 
 ## Todos
@@ -189,3 +220,14 @@ if show_history:
     - [x] import json
 
 - [x] support output of langchain' Agent.
+- [x] conext bound to chat
+
+# changelog
+
+## v1.1.12
+- fix type hint error with streamlit >= 1.33.0 (#8)
+- add ChatBox.change_chat_name to rename a chat conversation
+- maintain a context bound to chat conversation, it is like to be a sub session_state for every chat, context will get changed when you switch chat names.
+    - user can save chat bound values by `ChatBox.context['x'] = 1`
+    - values of widgets specified with a key can be saved to chat context with `ChatBox.context_from_session` and restored to st.session_state by `ChatBox.context_to_session`
+
diff --git a/example.py b/example.py
index 6a644ec..d1034c6 100644
--- a/example.py
+++ b/example.py
@@ -6,13 +6,21 @@
 
 llm = FakeLLM()
 chat_box = ChatBox()
+chat_box.use_chat_name("chat1") # add a chat conversatoin
+
+def on_chat_change():
+    chat_box.use_chat_name(st.session_state["chat_name"])
+    chat_box.context_to_session() # restore widget values to st.session_state when chat name changed
 
 
 with st.sidebar:
     st.subheader('start to chat using streamlit')
-    streaming = st.checkbox('streaming', True)
-    in_expander = st.checkbox('show messages in expander', True)
-    show_history = st.checkbox('show history', False)
+    chat_name = st.selectbox("Chat Session:", ["default", "chat1"], key="chat_name", on_change=on_chat_change)
+    chat_box.use_chat_name(chat_name)
+    streaming = st.checkbox('streaming', key="streaming")
+    in_expander = st.checkbox('show messages in expander', key="in_expander")
+    show_history = st.checkbox('show session state', key="show_history")
+    chat_box.context_from_session(exclude=["chat_name"]) # save widget values to chat context
 
     st.divider()
 
@@ -44,7 +52,7 @@ def on_feedback(
 
 feedback_kwargs = {
     "feedback_type": "thumbs",
-    "optional_text_label": "欢迎反馈您打分的理由",
+    "optional_text_label": "wellcome to feedback",
 }
 
 if query := st.chat_input('input your question here'):
@@ -137,4 +145,4 @@ def on_feedback(
 
 
 if show_history:
-    st.write(chat_box.history)
+    st.write(st.session_state)
diff --git a/setup.py b/setup.py
index 33c387e..b049a3a 100644
--- a/setup.py
+++ b/setup.py
@@ -9,7 +9,7 @@ def readme():
 
 setuptools.setup(
     name='streamlit-chatbox',
-    version='1.1.11',
+    version='1.1.12',
     author='liunux',
     author_email='liunux@qq.com',
     description='A chat box and some helpful tools used to build chatbot app with streamlit',
diff --git a/streamlit_chatbox/elements.py b/streamlit_chatbox/elements.py
index 213ac81..a415823 100644
--- a/streamlit_chatbox/elements.py
+++ b/streamlit_chatbox/elements.py
@@ -1,5 +1,6 @@
 from typing import *
 import streamlit as st
+from streamlit.delta_generator import DeltaGenerator
 # from pydantic import BaseModel, Field
 
 
@@ -40,7 +41,7 @@ def _set_default_kwargs(self) -> None:
             for k, v in default.items():
                 self._kwargs.setdefault(k, v)
 
-    def __call__(self, render_to: st._DeltaGenerator=None) -> st._DeltaGenerator:
+    def __call__(self, render_to: DeltaGenerator=None) -> DeltaGenerator:
         # assert self._dg is None, "Every element can be rendered once only."
         render_to = render_to or st
         self._place_holder = render_to.empty()
@@ -51,11 +52,11 @@ def __call__(self, render_to: st._DeltaGenerator=None) -> st._DeltaGenerator:
         return self._dg
 
     @property
-    def dg(self) -> st._DeltaGenerator:
+    def dg(self) -> DeltaGenerator:
         return self._dg
 
     @property
-    def place_holder(self) -> st._DeltaGenerator:
+    def place_holder(self) -> DeltaGenerator:
         return self._place_holder
 
     @property
@@ -132,7 +133,7 @@ def from_dict(cls, d: Dict) -> "OutputElement":
 
         return factory_cls(**kwargs)
 
-    def __call__(self, render_to: st._DeltaGenerator=None, direct: bool=False) -> st._DeltaGenerator:
+    def __call__(self, render_to: DeltaGenerator=None, direct: bool=False) -> DeltaGenerator:
         if render_to is None:
             if self._place_holder is None:
                 self._place_holder = st.empty()
@@ -158,7 +159,7 @@ def update_element(
         title: str = None,
         expanded: bool = None,
         state: bool = None,
-    ) -> st._DeltaGenerator:
+    ) -> DeltaGenerator:
         assert self.place_holder is not None, f"You must render the element {self} before setting new element."
         attrs = {}
         if title is not None:
diff --git a/streamlit_chatbox/messages.py b/streamlit_chatbox/messages.py
index 7f6d150..8a98a92 100644
--- a/streamlit_chatbox/messages.py
+++ b/streamlit_chatbox/messages.py
@@ -22,6 +22,23 @@
 }
 
 
+class AttrDict(dict):
+    def __getattr__(self, key: str) -> Any:
+        try:
+            return self[key]
+        except KeyError:
+            raise AttributeError(key)
+
+    def __setattr__(self, key: str, value: Any) -> None:
+        self[key] = value
+
+    def __delattr__(self, key: str) -> None:
+        try:
+            del self[key]
+        except KeyError:
+            raise AttributeError(key)
+
+
 class ChatBox:
     def __init__(
         self,
@@ -54,25 +71,33 @@ def init_session(self, clear: bool =False):
             time.sleep(0.1)
             self.reset_history(self._chat_name)
 
-    def reset_history(self, name=None):
+    def reset_history(self, name: str = None):
         if not self.chat_inited:
             st.session_state[self._session_key] = {}
 
-        name = name or self._chat_name
-        st.session_state[self._session_key][name] = []
+        name = name or self.cur_chat_name
+        st.session_state[self._session_key][name] = {"history": [], "context": AttrDict()}
         if self._greetings:
-            st.session_state[self._session_key][name] = [{
+            st.session_state[self._session_key][name]["history"] = [{
                     "role": "assistant",
                     "elements": self._greetings,
                     "metadata": {},
             }]
 
-    def use_chat_name(self, name: str ="default") -> None:
+    def use_chat_name(self, name: str = "default") -> None:
         self.init_session()
         self._chat_name = name
         if name not in st.session_state[self._session_key]:
             self.reset_history(name)
 
+    def change_chat_name(self, new_name: str, origin_name: str = None) -> bool:
+        self.init_session()
+        origin_name = origin_name or self.cur_chat_name
+        if (origin_name in st.session_state[self._session_key]
+            and new_name not in st.session_state[self._session_key]):
+            st.session_state[self._session_key][new_name] = st.session_state[self._session_key].pop(origin_name)
+            self._chat_name = new_name
+
     def del_chat_name(self, name: str):
         self.init_session()
         if name in st.session_state[self._session_key]:
@@ -88,15 +113,48 @@ def get_chat_names(self):
     def cur_chat_name(self):
         return self._chat_name
 
+    @property
+    def context(self) -> AttrDict:
+        self.init_session()
+        return st.session_state[self._session_key].get(self._chat_name, {}).get("context", AttrDict())
+
     @property
     def history(self) -> List:
         self.init_session()
-        return st.session_state[self._session_key].get(self._chat_name, [])
+        return st.session_state[self._session_key].get(self._chat_name, {}).get("history", [])
 
     def other_history(self, chat_name: str, default: List=[]) -> Optional[List]:
         self.init_session()
         chat_name = chat_name or self.cur_chat_name
-        return st.session_state[self._session_key].get(chat_name, default)
+        return st.session_state[self._session_key].get(chat_name, {}).get("history", default)
+
+    def other_context(self, chat_name: str, default: AttrDict=AttrDict()) -> AttrDict:
+        self.init_session()
+        chat_name = chat_name or self.cur_chat_name
+        return st.session_state[self._session_key].get(chat_name, {}).get("context", default)
+
+    def context_to_session(self, chat_name: str=None, include: List[str]=[], exclude: List[str]=[]) -> None:
+        '''
+        copy context to st.session_state.
+        copy named variables only if `kw` specified
+        this can be usefull to restore session_state when you switch between chat conversations
+        '''
+        for k, v in self.other_context(chat_name).items():
+            if (not include or k in include
+                and k not in exclude):
+                st.session_state[k] = v
+
+    def context_from_session(self, chat_name: str=None, include: List[str]=[], exclude: List[str]=[]) -> None:
+        '''
+        copy context from st.session_state.
+        copy named variables only if `kw` specified
+        this can be usefull to save session_state when you switch between chat conversations
+        '''
+        for k, v in st.session_state.items():
+            if ((not include or k in include)
+                and k not in exclude
+                and k != self._session_key):
+                self.other_context(chat_name)[k] = v
 
     def filter_history(
         self,
@@ -194,7 +252,7 @@ def to_dict(
         self,
     ) -> Dict:
         '''
-        export current state to dict
+        export current state including messages and context to dict
         '''
         self.init_session()
 
@@ -208,7 +266,7 @@ def p(val):
             else:
                 return val
 
-        histories = {x: p(self.other_history(x)) for x in self.get_chat_names()}
+        histories = {x: p({"history": self.other_history(x), "context": self.other_context(x)}) for x in self.get_chat_names()}
         return {
             "cur_chat_name": self.cur_chat_name,
             "session_key": self._session_key,
@@ -246,11 +304,12 @@ def from_dict(
             self.reset_history(name)
             for h in history:
                 msg = {
-                    "role": h["role"],
-                    "elements": [OutputElement.from_dict(y) for y in h["elements"]],
-                    "metadata": h["metadata"],
+                    "role": h["history"]["role"],
+                    "elements": [OutputElement.from_dict(y) for y in h["history"]["elements"]],
+                    "metadata": h["history"]["metadata"],
                     }
                 self.other_history(name).append(msg)
+                self.other_context(name).update(h["context"])
 
         self.use_chat_name(data["cur_chat_name"])
         return self
@@ -348,7 +407,7 @@ def update_msg(
         expanded: bool = None,
         state: bool = None,
         metadata: Dict = {},
-    ) -> st._DeltaGenerator:
+    ) -> DeltaGenerator:
         self.init_session()
         if not self.history or not self.history[history_index]["elements"]:
             return