Two generator in gradio.ChatInterface function, but only show one

Describe the bug

Thanks for your excellent job! I used gradio.ChatInterface to build a llm web rebot, I want to yield from two variables in the chat function, but when the second generator output, the first generotor content is gone, only the second generator content show in the chatbot UI.

Have you searched existing issues? 🔎

[X] I have searched and found no existing issues

Reproduction

    def chat(self, message: str, history: List[List[str]]) -> Iterator[str]:
        for human, assistant in history:
            self.messages.append({"role": "user", "content": human})
            self.messages.append({"role": "assistant", "content": assistant})
        self.messages.append({"role": "user", "content": self.rag(message)})

        responses = dashscope.Generation.call(model=self.llm_info['Model'],
                                              api_key=self.llm_info['Key'],
                                              messages=self.messages,
                                              result_format='message',
                                              stream=True)
        for response in responses:
            response_content = response.output.choices[0]['message']['content']
            yield response_content

        for i, title in enumerate(self.refer_titles, 1):
            refer_title = f'[{i}] {title}'
            yield refer_title

Screenshot

No response

Logs

No response

System Info

Gradio Environment Information:
------------------------------
Operating System: Windows
gradio version: 4.37.2
gradio_client version: 1.0.2

------------------------------------------------
gradio dependencies in your environment:

aiofiles: 23.2.1
altair: 5.3.0
fastapi: 0.111.0
ffmpy: 0.3.2
gradio-client==1.0.2 is not installed.
httpx: 0.26.0
huggingface-hub: 0.22.2
importlib-resources: 6.4.0
jinja2: 3.1.2
markupsafe: 2.1.1
matplotlib: 3.7.0
numpy: 1.23.5
orjson: 3.10.1
packaging: 23.2
pandas: 1.5.3
pillow: 9.4.0
pydantic: 2.8.2
pydub: 0.25.1
python-multipart: 0.0.9
pyyaml: 6.0.1
ruff: 0.5.1
semantic-version: 2.10.0
tomlkit==0.12.0 is not installed.
typer: 0.12.3
typing-extensions: 4.9.0
urllib3: 1.26.19
uvicorn: 0.22.0
authlib; extra == 'oauth' is not installed.
itsdangerous; extra == 'oauth' is not installed.

gradio_client dependencies in your environment:

fsspec: 2024.3.1
httpx: 0.26.0
huggingface-hub: 0.22.2
packaging: 23.2
typing-extensions: 4.9.0
websockets: 11.0.3

Severity

I can work around it

gradio-app / gradio

Two generator in gradio.ChatInterface function, but only show one #8734