assistant2: Don't scroll down if user has scrolled up (#27614)

Richard Feldman and Agus created 10 months ago

This caused undesirable and unnecessary scrolling, in that if you scroll
up, then as new messages stream into the panel, they jump the scroll bar
back down.

@agu-z and I paired on this and we think this is unnecessary now that we
don't see the Edit button in the UI, but @bennetbo we still see code for
the button in there, so...maybe we do still want this? (If so, we can
revert the second commit and go back to a more conditional way of
scrolling. 😄)

Release Notes:

- N/A

---------

Co-authored-by: Agus <[e-mail]>

Change summary

crates/assistant2/src/active_thread.rs | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

Detailed changes

crates/assistant2/src/active_thread.rs

@@ -12,9 +12,9 @@ use editor::{Editor, MultiBuffer};
 use gpui::{
     linear_color_stop, linear_gradient, list, percentage, pulsating_between, AbsoluteLength,
     Animation, AnimationExt, AnyElement, App, ClickEvent, DefiniteLength, EdgesRefinement, Empty,
-    Entity, Focusable, Hsla, Length, ListAlignment, ListOffset, ListState, MouseButton,
-    ScrollHandle, Stateful, StyleRefinement, Subscription, Task, TextStyleRefinement,
-    Transformation, UnderlineStyle, WeakEntity, WindowHandle,
+    Entity, Focusable, Hsla, Length, ListAlignment, ListState, MouseButton, ScrollHandle, Stateful,
+    StyleRefinement, Subscription, Task, TextStyleRefinement, Transformation, UnderlineStyle,
+    WeakEntity, WindowHandle,
 };
 use language::{Buffer, LanguageRegistry};
 use language_model::{LanguageModelRegistry, LanguageModelToolUseId, Role};
@@ -317,10 +317,6 @@ impl ActiveThread {
         let rendered_message =
             RenderedMessage::from_segments(segments, self.language_registry.clone(), window, cx);
         self.rendered_messages_by_id.insert(*id, rendered_message);
-        self.list_state.scroll_to(ListOffset {
-            item_ix: old_len,
-            offset_in_item: Pixels(0.0),
-        });
     }
 
     fn edited_message(