Autoscroll for streaming textbox fails

[easyfacelab]

Describe the bug

My multi-tabbed app uses multiple Textboxes, one of them to show app logs.
As per the doc, the textbox should always go to the bottom, but that's not true when you switch from one tab to another.
From some reason, I cannot reproduce as easily without these tabs.
On Chrome the problem appears after switching multiple times, sometimes after launching several time the script doing a stream in my example. On Firefox, the problem appears on the first switch between the tabs.
This looks like a pure js issue, and this is precisely why I'm using Gradio, being not a web dev.
Is there a design issue in the way I manage the streams in the callbacks? Or could it be a Gradio limitation?

I'm sharing a minimal reproducer. Thanks for any enlightenment.

Relates: #5417, #6085

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Reproduction

import subprocess
import time
import gradio as gr

def read_external_program():
    # simple bash loop writing into /tmp/log during 20s
    cmd = ['/bin/bash', '-c', 'for ((x=0; x<20; x=x+1)); do echo $x |& tee -a /tmp/log; sleep 1; done; exit 2']
    p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, universal_newlines=True)
    output = ""
    while p.poll() is None:
        output += p.stdout.readline()
        yield output, '0'
    ret = p.wait()
    yield output, ret

def read_logs():
    output = ""
    with open('/tmp/log') as f:
        while True:
            for line in f:
                output += line
                yield output
            time.sleep(0.1)

with gr.Blocks() as demo:
    with gr.Tab('program'):
        prog_out = gr.Textbox(label='program output', interactive=False, lines=10, max_lines=10)
        return_code = gr.Textbox(label='exit code', interactive=False, value='0')
        start_btn = gr.Button('start')
        start_btn.click(read_external_program, None, [prog_out, return_code])
    with gr.Tab('log'):
        logbox = gr.Textbox(label='log file', interactive=False, lines=35, max_lines=35)
        refresh_btn = gr.Button('refresh logs')
        refresh_btn.click(read_logs, None, logbox)

demo.launch()

Screenshot

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Logs

System Info

Gradio 5.14.0
Ubuntu 24.04 LTS
Chrome 132.0.6834.83
Firefox 135.0

Severity

Blocking usage of gradio