agent: Add small UI fixes (#38231)

Release Notes:

- N/A

crates/agent_ui/src/acp/thread_history.rs

@@ -500,20 +500,24 @@ impl Render for AcpThreadHistory {
                         ),
                     )
                 } else {
-                    view.pr_5()
-                        .child(
-                            uniform_list(
-                                "thread-history",
-                                self.visible_items.len(),
-                                cx.processor(|this, range: Range<usize>, window, cx| {
-                                    this.render_list_items(range, window, cx)
-                                }),
-                            )
-                            .p_1()
-                            .track_scroll(self.scroll_handle.clone())
-                            .flex_grow(),
+                    view.child(
+                        uniform_list(
+                            "thread-history",
+                            self.visible_items.len(),
+                            cx.processor(|this, range: Range<usize>, window, cx| {
+                                this.render_list_items(range, window, cx)
+                            }),
                         )
-                        .vertical_scrollbar_for(self.scroll_handle.clone(), window, cx)
+                        .p_1()
+                        .pr_4()
+                        .track_scroll(self.scroll_handle.clone())
+                        .flex_grow(),
+                    )
+                    .vertical_scrollbar_for(
+                        self.scroll_handle.clone(),
+                        window,
+                        cx,
+                    )
                 }
             })
     }

crates/agent_ui/src/acp/thread_view.rs

@@ -3182,10 +3182,14 @@ impl AcpThreadView {
                                     };
 
                                     Button::new(SharedString::from(method_id.clone()), name)
-                                        .when(ix == 0, |el| {
-                                            el.style(ButtonStyle::Tinted(ui::TintColor::Warning))
-                                        })
                                         .label_size(LabelSize::Small)
+                                        .map(|this| {
+                                            if ix == 0 {
+                                                this.style(ButtonStyle::Tinted(TintColor::Warning))
+                                            } else {
+                                                this.style(ButtonStyle::Outlined)
+                                            }
+                                        })
                                         .on_click({
                                             cx.listener(move |this, _, window, cx| {
                                                 telemetry::event!(