[BUG] auto-scroll feature for new responses

[ryu-shen]

Environment

Big-AGI Pro (big-agi.com)

Description

The AI chat interface lacks an auto-scroll feature for new responses. Users are forced to manually navigate to the bottom of the chat history after every reply, resulting in a poor user experience

Device and browser

Windows 11
Chrome

Screenshots and more

No response

Willingness to Contribute

• 🙋‍♂️ Yes, I would like to contribute a fix.

[github-actions]

Thanks for the report @ryu-shen.

Assessment

Big-AGI does have an auto-scroll (stick-to-bottom) system, implemented in src/common/scroll-to-bottom/ScrollToBottom.tsx. It is enabled for the main chat via stickToBottomInitial in src/apps/chat/AppChat.tsx:694-696. Here's how it works:

• A ResizeObserver monitors children of the scrollable container. When content grows (new streaming tokens, new messages), it triggers scrollTo({ top: scrollHeight, behavior: 'smooth' }) if stickToBottom is true.
• A scroll event listener detects user intent: if you scroll within 60px of the bottom, stickToBottom re-enables; if you scroll up, it disables.
• A floating button (down-arrow FAB) appears when you're not at the bottom, letting you re-stick with one click.

So auto-scroll should already be working. A few things to investigate:

Possible causes

1. Smooth scroll race condition - When scrollTo({ behavior: 'smooth' }) fires, it generates multiple scroll events over the animation. Only the first is suppressed as programmatic (isProgrammaticScroll ref). Subsequent intermediate events during the animation can detect the scroll position as "not at bottom" and set stickToBottom = false, breaking auto-scroll until the user manually scrolls back down. This is a known class of issue with smooth scrolling + scroll listeners.

2. Browser extension or setting - Chrome extensions that modify scroll behavior (smooth scroll extensions, ad blockers injecting content, etc.) could interfere.

3. Zoom level or display scaling - On Windows 11 with non-100% display scaling, fractional pixel calculations in the at-bottom check (scrollHeight - scrollTop <= offsetHeight + 60) could be slightly off.

Debugging steps

Could you try the following and report back?

1. Check if the floating scroll-to-bottom button appears (down-arrow icon in the bottom-right of the chat area). If it appears, auto-scroll is present but stickToBottom is getting disabled.
2. Try with extensions disabled (incognito mode) to rule out interference.
3. Check display scaling (Windows Settings > Display > Scale) - if not at 100%, note the value.
4. Check browser zoom - ensure it's at 100% (Ctrl+0 to reset).

Workaround

If the scroll-to-bottom button appears, clicking it will re-enable stick-to-bottom for the current session.

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Triaged by Claude

[DoS007]

@ryu-shen I tested it (open big-agi). There might have been such a feature. But if i tested it right, it also doesn't work for me (on desktop). On mobile it maybe works? Can't say when it stopped to work on destop because I don't like it that much, because for reading it's in my opinion nicer to have a not moving text.

[enricoros]

@DoS007 @ryu-shen I can confirm that I'm seeing the issue myself too. Not all the times, just sometimes. Do you have a way to reproduce this very reliably? (also, agree with your statement on reading with still text)